The House of Lords is due to debate the following motion on 18 January 2024:

Lord Trees (Crossbench) to move that this House takes note of biosecurity, and the threat of infectious diseases for human, animal and plant health, in an age of globalisation and climate change.

1. What is biosecurity?

The term biological security, or biosecurity, has a variety of meanings. The UK government uses the following definition:

[…] the protection of the UK and UK interests from biological risks whether these arise naturally, or through an accidental release of hazardous biological material, or a deliberate biological attack. These risks could affect humans, animals, plants or the environment more broadly.[1]

The Joint Committee on the National Security Strategy used a very similar definition during its inquiry into biosecurity and national security in the 2019–21 parliamentary session.[2]

2. Threats posed by infectious diseases

2.1 Overview

The coronavirus pandemic showed that the UK is at risk of the spread of infectious diseases that can have considerable impacts on public health and the economy. Covid-19 is an example of a zoonosis—a disease that was transmitted between animals and humans. It has been estimated that 75% of new diseases in humans in recent decades have been zoonoses, including HIV, Ebola, Zika, swine flu (H1N1), and Covid-19.[3] There is evidence that the number of emerging zoonoses is increasing globally, driven by factors such as a rising global population, climate change, biodiversity loss, land use change, and increased trade in pets, meat and other products.[4]

There is also evidence that climate change could increase the prevalence of vector-borne diseases (VBDs) in the UK.[5] VBDs are transmitted between affected humans and animals by other living organisms, such as mosquitoes, lice and ticks.[6] Mosquitoes can transmit a range of diseases, including malaria, dengue, Zika, and West Nile fever. Fleas and lice can transmit diseases such as plague and typhus respectively. Ticks can spread Lyme disease and encephalitis.

Animals are also at risk from a range of other diseases, including endemic diseases such as bovine tuberculosis and exotic diseases such as foot and mouth disease.[7]

Tree and plant health may also be affected by organisms, including pests, in natural or cultivated settings. These may include insects or pathogens such as bacteria, viruses and fungi.[8]

2.2 Impact of climate change on infectious diseases

Climate change is projected to be a specific driver of infectious disease globally. The UN’s Intergovernmental Panel on Climate Change (IPCC) publishes periodic reports which collate the latest scientific assessments of climate change and its impacts. Its ‘Climate change 2023: Synthesis report’ (March 2023) concluded that “human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming”.[9] The report stated that climate change had already caused an increase in disease transmission globally:

In all regions increases in extreme heat events have resulted in human mortality and morbidity. The occurrence of climate-related food-borne and water-borne diseases and the incidence of vector-borne diseases have increased.[10]

The IPCC concluded that in the near term (up to 2040) all regions of the world would experience an increase in infectious disease due to climate change. It stated:

In the near term, every region in the world is projected to face further increases in climate hazards increasing multiple risks to ecosystems and humans. Hazards and associated risks expected in the near term include an increase in heat-related human mortality and morbidity, food-borne, water-borne, and vector-borne diseases.[11]

The UK’s Climate Change Committee, a statutory body that advises the government, commissioned an independent risk assessment of the specific impacts of climate change on the UK.[12] Specifically on health impacts, a resulting report concluded that a range of tick- and mosquito-transmitted diseases could increase due to rising temperatures. The report stated:

Climate change is projected to increase the risk of vector-borne diseases in the UK, particularly in southern England. Hot summers have already affected transmission dynamics for vector-borne disease. The mosquito vector of dengue has been found in the UK for the first time. Lyme disease cases may increase with climate change due to an extended transmission season and increases in person-tick contact. The risk of mosquito-transmitted diseases such as chikungunya and dengue fever is likely to increase in England and Wales as temperatures rise. The risk that malaria may become established remains low. The risk of [Culex mosquito]-transmitted diseases such as West Nile virus could increase in the UK.[13]

The UK Health Security Agency (UKHSA) is an executive agency of the Department of Health and Social Care. It has responsibility for protecting the UK from infectious diseases and biological threats affecting humans. In December 2023, the UKHSA published a report entitled ‘Health effects of climate change in the UK: State of the evidence 2023’. Chapter seven of the report focused on the impact of climate change on infectious diseases, providing an assessment of the risks from a range of bacteria, viruses and parasites. Chapter eight of the report focused on vector-borne diseases.

Chapter seven stated that, although the effect of climatic factors on infectious diseases was complex, there was evidence that “climate change is and will continue to affect infectious diseases” through a range of “ecological, biological and social mechanisms”.[14] For example, there may be “longer transmission periods associated with warmer conditions” and “the emergence of novel species may be influenced”. It also estimated that human behavioural changes could be associated with climate change. Food-borne diseases may increase from “warmer weather resulting in changed food preparation and consumption patterns”. Increased countryside visits may in turn increase “potential exposure to infectious disease hazards”. The report also highlighted the potential economic impact of increased disease transmission. It said the economic burden from infectious diseases in the UK was “£30bn annually, dominated by respiratory and gastrointestinal infections”.[15]

Chapter seven also stated that the impacts of climate change on human health would occur concurrently with two other trends in the UK: an ageing population and increased anti-microbial resistance (AMR). The report estimated that by 2066 there would be an additional 8.6 million people in the UK aged 65 and over, comprising 26% of the population. It also said that AMR “poses a growing threat to human, animal and environmental health”. It added there was emerging evidence that AMR may be influenced by climate change:

Warming temperatures may accelerate bacterial growth, increase bacterial infection rates, increase the frequency of infections in healthcare settings and expand geographical distributions. These processes increase the likelihood of horizontal gene transfer and thus the emergence of drug-resistant infections.[16]

Chapter eight of the report focused on vector-borne diseases.[17] It stated that VBDs are “highly climate sensitive” and that higher temperatures were a recognised driver of “tick and mosquito presence, distribution and seasonality”.[18] The report stated that its analyses were based on a “high-end warming scenario” of approximately 4.3°C of warming. Projections were therefore “worst-case scenario estimates in the absence of climate change mitigation and adaptation”. The report set out its projections for tick- and mosquito-borne diseases in the UK given these assumptions.

The report stated that Lyme disease and encephalitis were the tick-borne diseases of greatest concern. It stated that while Lyme disease incidence was “already increasing in the UK”, the risk from encephalitis was “currently very low”.[19] Increases in these two diseases were the “most likely emergent tick-borne risks in the UK as the climate warms”.

On mosquito-borne disease risks, the report stated:

A concern under warming temperatures is the potential introduction and establishment of invasive mosquito species in the UK, particularly Aedes albopictus, an aggressive daytime biting mosquito species that can transmit several arboviruses of public health concern, including dengue, chikungunya and Zika. Climate modelling suggests that the area around London already has a suitable climate for Ae. albopictus survival, and most of England will become suitable for its establishment by the 2040s and 2050s. Under this reasonable worst-case scenario, by the 2060s or 2070s, most of Wales, Northern Ireland and parts of the Scottish Lowlands could also become suitable. It is expected that London could become suitable for endemic dengue transmission as early as the 2060s under a high-warming scenario. Similarly, high-warming scenarios indicate the potential suitability for chikungunya transmission in the UK beginning in the latter half of the century, with spread linked to rate of warming. This evidence indicates that the establishment of Ae. albopictus in the UK is one of the most significant risks for public health posed by climate change.[20]

The report summarised what actions the UKHSA was taking to monitor tick and mosquito populations in the UK:

UKHSA monitors tick and mosquito populations through both passive and active surveillance activities, and also monitors for non-native vectors. UKHSA has contributed to developing a cross-government contingency plan following the detection of invasive mosquitoes in England, which involves a network of invasive mosquito trapping locations coordinated by UKHSA. In addition, UKHSA is a member of the Human Animal Infections Risk Surveillance (HAIRS) group, which is a multi-agency cross-government horizon scanning and risk assessment group, aiming to identify and risk assess emerging and potentially zoonotic infections which may pose a threat to UK public health.[21]

Climate change is also exacerbating the risk of disease in animals and plants. Regarding the natural environment, the government’s third national adaptation programme, published in July 2023, observed:

Climate risks across the natural environment are highly connected, as ecosystems do not function in isolation. There are many interactions between climate change impacts to different terrestrial, freshwater, coastal and marine habitats. For example, projected trends of warmer wetter winters will increase instances of water flowing over land and into habitats such as rivers, lakes, wetlands and estuaries. These flows of water can carry nutrients, agri-chemicals, seeds and other material with them, promoting the spread of pollution, invasive non-native species (INNS), pests and diseases across habitats.[22]

3. Addressing biosecurity: UK government policy

3.1 UK biological security strategy

The current UK biological security strategy was published in June 2023.[23] It provides the “overarching strategic framework for mitigating biological risks”.[24] The first biological security strategy was published in July 2018.[25]

The 2023 strategy said the Covid-19 pandemic had shown that the “UK, as a global trading and tourism hub, is vulnerable to biological threats with catastrophic impacts”.[26] It said there was a “reasonable likelihood” that another pandemic could occur “within the next decade”. It also stated that the risk of new pathogens emerging had risen as “trade, tourism and migration increases and as climate change affects the distribution of disease vectors and biodiversity”.

In addition to potential disease outbreaks, the strategy also highlighted other risks, including:

  • increased anti-microbial resistance
  • a deliberate biological attack by state or non-state actors
  • accidental release of a pathogen

The strategy set out the government’s vision that, by 2030, the UK would be “resilient to a spectrum of biological threats, and a world leader in responsible innovation, making a positive impact on global health, economic and security outcomes.[27]

The document added the government’s strategic framework would be built on the following four pillars:

  • Understand the biological risks we face today and could face in the future.
  • Prevent biological risks from emerging (where possible) or from threatening the UK and UK interests.
  • Detect, characterise and report biological risks when they do emerge as early and reliably as possible.
  • Respond to biological risks that have reached the UK or UK interests to lessen their impact and to enable a rapid return to business as usual.

The strategy stated that there were also opportunities for the UK in helping to develop “breakthrough inventions and innovations” to counter biological threats.[28] It said the UK was “well positioned” to seize the opportunities by stimulating its “vibrant life sciences and artificial intelligence sectors to develop market-leading biosecurity solutions”.

In a House of Commons written statement to accompany the publication of the biological security strategy, the deputy prime minister, Oliver Dowden, provided further information on how the strategy would be implemented.[29] Commitments included:

  • developing a biothreats radar and national bio-surveillance network to detect and monitor emerging biological threats to the UK
  • establishing a new UK biosecurity leadership council, bringing together academic and industry leaders to help establish the UK as a world leader in responsible innovation
  • developing new UK-based microbial forensics tools and capabilities to support efforts to attribute biological incidents and deter the proliferation and use of biological weapons
  • formalising the leadership structures that oversee our biological security—including a lead minister who will report annually to Parliament
  • establishing a biological security taskforce in the Cabinet Office to coordinate UK-wide efforts on biological security, including exercising our response to future threats

Lord Douglas-Miller has served as the government’s biosecurity minister since 1 December 2023.[30]

The UK, Scottish and Welsh governments have published a separate ‘Plant biosecurity strategy for Great Britain (2023 to 2028)’ setting out how the Department for Environment, Food and Rural Affairs, the Forestry Commission and the devolved governments in Scotland and Wales will work together to protect plant biosecurity in Great Britain.[31] Defra has also previously published a tree health resilience strategy and a food strategy.[32] The latter included information on government measures to control endemic disease in farmed animals.

3.1.1 Responses to the biological security strategy

A joint response to the strategy from the Centre for Long-Term Resilience (CLTR) think tank and Cambridge University’s Centre for the Study of Existential Risk (CSER) said that it welcomed many of the commitments in the document.[33] The response welcomed commitments to “formalise the government’s biosecurity leadership” structures and to invest in “real-time bio-surveillance and detection capabilities”. It also referred to a government press release that had accompanied the publication of the biosecurity strategy, in which the government had committed to £1.5bn of funding each year.[34] The response said it was not clear if that was newly allocated funding. It urged the government to fund the strategy at a “level of investment commensurate with the seriousness of these risks”, which would demand “significant financial resources if they are to be adequately addressed”.

The Council on Strategic Risks (CSR) think tank said the strategy “signals important policy shifts” to achieve resilience to biological threats by 2030.[35] It noted that the UK’s strategy appeared to “closely align” with the US’s ‘National biodefense strategy and implementation plan’, published in October 2022. CSR said that both strategies had an emphasis on clearer government leadership, preventative measures and improved early-warning capabilities. It said that one area of divergence was on funding. While the UK had made a “laudable” commitment of £1.5bn a year, the US strategy “was not accompanied by dedicated funding to support implementation”. The CSR concluded that the UK’s strategy was an “important step in improving health security in the UK and internationally”, but there now needed to be “sustained attention on implementation”.

3.2 Import controls: The UK border target operating model

The government has emphasised that border controls are an important part of the UK’s biosecurity regime.[36] At the end of the Brexit transition period on 31 December 2020, the EU imposed its full third-country customs and regulatory regime to goods imported from Great Britain. Although the UK applies customs formalities to high-risk imports, such as live animals and plants, the UK government has repeatedly delayed applying full third-country customs and regulatory checks to goods, including food products, entering from the EU.[37]

The government has said that the delays to implementing import controls on goods from the EU were a pragmatic response to give importers time to adapt and prepare for the new border regime during a period of high inflation.[38] However, the delays have been criticised by some parts of the food and agriculture sectors. In February 2023 it was reported that the president of the National Farmers’ Union, Minette Batters, had said that the UK was “in danger of a disastrous food scandal, owing to lax post-Brexit border controls on agricultural imports” from the EU.[39]

In August 2023, the government published its plans for “a new approach to importing goods into Great Britain”, called the ‘border target operating model’ (BTOM).[40] The government has described the BTOM as follows:

The border target operating model sets out our new approach to safety and security controls (applying to all imports), and sanitary and phytosanitary controls (applying to imports of live animals, germinal products, animal products, plants and plant products) at the border.[41]

The BTOM referred to the government’s biological security strategy and set out the importance of border checks for preventing disease transmission in the UK:

Large scale disease outbreaks in animals or plants do not respect international boundaries and the threat they pose has grown as the world becomes increasingly interconnected. As a global trading nation, the UK is exposed to these risks, and border controls are a key tool to manage them.[42]

It continued:

At present, goods from the EU enter the UK without certification and checks, apart from those required for the highest risk items, such as live animals, germinal products and plants. The border target operating model introduces proportionate controls that will protect the agri-food sector and public health. These are vital to avoid diseases that could devastate UK industries and our ability to export.

The BTOM contained a case study on African swine fever.[43] It said that an outbreak of the disease in the UK “would be a fundamental threat to the viability of our pig industry”. Although the document confirmed that no cases of African swine fever had yet been confirmed in the UK, routine inspections of UK retailers had “detected frozen, raw and uncooked meat products marked clearly as suitable only for sale in the originating country”. Although the products did not test positive for African swine fever on that occasion, the BTOM stated that “the very fact that these products reached the UK presents a serious and immediate threat to the UK pig industry”.

The BTOM is due to be progressively introduced from the end of January 2024:

  • 31 January 2024: The introduction of health certification on imports of medium risk animal products, plants, plant products and high-risk food and feed of non-animal origin from the EU. The removal of pre-notification requirements for low-risk plant and plant products from the EU.
  • 30 April 2024: The introduction of documentary and risk-based identity and physical checks on medium risk animal products, plants, plant products and high-risk food and feed of non-animal origin from the EU.
  • 31 October 2024: The requirement for safety and security declarations for imports into Great Britain from the EU.[44]

The government said it was phasing in the BTOM for several reasons, including the need for effective management of biosecurity:

We will introduce the new model in a phased approach that balances several factors: the need for effective management of biosecurity, public health, food safety and security risks; the need to give businesses sufficient time to prepare; the need to ensure supply chains have time to adapt and are not disrupted; and the speed at which we can work with stakeholders to build the systems and infrastructure required under the new model, including the rollout of the UK single trade window.[45]

On 9 January 2024 Defra laid a statutory instrument before Parliament providing for the existing exemption for health certificates and phytosanitary certificates for goods classified as medium risk to end from 31 January 2024.[46]

3.2.1 Responses to the border operating model

The National Farmers’ Union responded to the publication of the BTOM by saying that the previous delays to its implementation had been “hugely frustrating” for agri-food importers and for farmers that exported, as they were not facing a level playing field compared to their EU competitors.[47] Minette Batters said the introduction of the BTOM regime was not only necessary to create a level playing field, but also for reasons of biosecurity. She stated:

Proportionate and effective controls [on imports] are necessary if we are to prevent outbreaks of pests and diseases that threaten human, animal and plant health, the safety, quality and biosecurity of our food products and the confidence of our trading partners.[48]

The British International Freight Association (BIFA) said that the implementation of the BTOM, coupled with uncertainty caused by previous delays to the regime, would mean “a very hectic start to the new year” for its members.[49] BIFA said that although certain parts of the BTOM published in August 2023 were “an improvement over its previous incarnation”, it still did not address “fundamental concerns” BIFA had raised with the government regarding the “suitability of using the present port health authorities to handle international trade”. BIFA also said that the implementation of the BTOM was reliant on the launch of the government’s ‘single trade window’ digital gateway, which it said was “still very much under development”.

In a House of Commons debate on the BTOM and its impact on food prices on 7 September 2023, Labour’s shadow Cabinet Office minister, and former shadow secretary of state for international trade, Nick Thomas-Symonds, said:

[The BTOM] document concedes that these measures, when introduced, will have an impact on inflation and will make the cost of food even higher. Can the minister set out what assessment has been made of the wasted money and the cost to taxpayers and businesses as a result of the government’s chaos on this issue?[50]

In response, Parliamentary Secretary for the Cabinet Office Alex Burghart stated:

[The government] delayed implementation in response to the [inflationary] challenges the country has faced. We are now ready to move forward with a brand-new border target operating model, which has the support of businesses, of vets and of those dealing with sanitary and phytosanitary checks. It will be a very good thing for the country and will help us to secure our borders in new ways.[51]

4. Read more

House of Lords Library:

Parliamentary Office of Science and Technology:

Parliamentary material:

Other material:

Cover image by Nadya on Pixabay.


  1. HM Government, ‘UK biological security strategy’, 12 June 2023, CP 858, p 77. Return to text
  2. Joint Committee on the National Security Strategy, ‘Biosecurity and national security’, 18 December 2020, HL Paper 195 of session 2019–21, pp 5–6. Return to text
  3. Parliamentary Office of Science and Technology, ‘Preventing emerging zoonoses’, 7 January 2022, p 1. Return to text
  4. As above; and Parliamentary Office of Science and Technology, ‘Public health and climate change: A one health approach’, 19 July 2023. Return to text
  5. Parliamentary Office of Science and Technology, ‘Climate change and vector-borne disease in humans in the UK’, 10 April 2019. Return to text
  6. World Health Organization, ‘Vector-borne diseases’, 2 March 2020. Return to text
  7. Department for Environment, Food and Rural Affairs, ‘Notifiable diseases in animals’, updated 14 March 2019. Return to text
  8. Parliamentary Office of Science and Technology, ‘Plant biosecurity in Great Britain’, 4 July 2023. Return to text
  9. Intergovernmental Panel on Climate Change, ‘Climate change 2023: Synthesis report—summary for policymakers’, 2023, p 4. Return to text
  10. As above, p 6. Return to text
  11. As above, p 15. Return to text
  12. Climate Change Committee/UK Climate Risk, ‘Technical report (CCRA3-IA)’, 16 June 2021. Return to text
  13. Climate Change Committee/UK Climate Risk, ‘Technical report (CCRA3-IA): Chapter 5—health, communities and built environment’, 16 June 2021. Return to text
  14. UK Health Security Agency, ‘Health effects of climate change (HECC) in the UK: 2023 report. Chapter 7: Effect of climate change on infectious diseases in the UK’, December 2023, p 7. Return to text
  15. As above. Return to text
  16. As above, pp 7–8. Return to text
  17. UK Health Security Agency, ‘Health effects of climate change (HECC) in the UK: 2023 report. Chapter 8: Direct and indirect effects of climate change on vectors and vector-borne diseases in the UK’, December 2023. Return to text
  18. As above, p 2. Return to text
  19. As above. Return to text
  20. As above. Return to text
  21. As above, p 3. Return to text
  22. HM Government, The third national adaptation programme (NAP3) and the fourth strategy for climate adaptation reporting, updated 21 July 2023, p 50. Return to text
  23. HM Government, ‘UK biological security strategy’, 12 June 2023, CP 858. Return to text
  24. As above, p 8. Return to text
  25. HM Government, ‘UK biological security strategy (2018)’, July 2018. Return to text
  26. HM Government, ‘UK biological security strategy’, 12 June 2023, CP 858, p 15. Return to text
  27. As above, p 8. Return to text
  28. As above, p 16. Return to text
  29. House of Commons, ‘Written statement: Publication of the 2023 UK biological security strategy (HCWS841)’, 12 June 2023. Return to text
  30. HM Government, ‘Robbie Douglas-Miller OBE’, accessed 10 January 2024; and UK Parliament, ‘Lord Douglas-Miller: Parliamentary career’, accessed 10 January 2024. Return to text
  31. Department for Environment, Food and Rural Affairs, ‘Plant biosecurity strategy for Great Britain (2023 to 2028)’, 9 January 2023. Return to text
  32. Department for Environment, Food and Rural Affairs, ‘Tree health resilience strategy’, 25 May 2018; and ‘Government food strategy’, 13 June 2022, CP 698. Return to text
  33. Centre for Long-Term Resilience, ‘Response to the UK government’s refreshed biological security strategy (BSS)’, 19 June 2023. Return to text
  34. Cabinet Office, ‘Dowden: World-class crisis capabilities deployed to defeat biological threats of tomorrow’, 12 June 2023. Return to text
  35. Council on Strategic Risks, ‘Review: The UK government’s updated biological security strategy’, 28 June 2023. Return to text
  36. Cabinet Office, ‘New border controls to protect the UK against security and biosecurity threats and ensure smooth flow of goods’, 29 August 2023. Return to text
  37. Reuters, ‘Britain delays post-Brexit border checks on EU goods till 2024’, 29 August 2023. Return to text
  38. George Parker, ‘UK to confirm further delay to post-Brexit border controls’, Financial Times (£), 24 August 2023. Return to text
  39. Fiona Harvey, ‘UK risks ‘disastrous’ food scandal due to lax post-Brexit border controls—NFU chief’, Guardian, 17 February 2023. Return to text
  40. Cabinet Office, ‘Guidance: The border target operating model—August 2023’, 29 August 2023. Return to text
  41. Cabinet Office, ‘The border target operating model: August 2023’, 29 August 2023, p 12. Return to text
  42. As above, p 21. Return to text
  43. As above, p 22. Return to text
  44. As above, p 13. Return to text
  45. As above. Return to text
  46. UK Parliament, ‘Official Controls (Extension of Transitional Periods) (Miscellaneous Amendments) Regulations 2024’, accessed 10 January 2024. Return to text
  47. National Farmers’ Union, ‘Border checks on EU imports delayed for fifth time’, 30 August 2023. Return to text
  48. As above. Return to text
  49. British International Freight Association, ‘UK freight association comments on updated border target operating model’, 30 August 2023. Return to text
  50. HC Hansard, 7 September 2023, col 529. Return to text
  51. HC Hansard, 7 September 2023, col 529. Return to text