The Salisbury-Addison Convention is commonly understood to mean that the House of Lords gives a second reading to government bills which seek to implement manifesto commitments, and that the House does not table wrecking amendments which might otherwise alter the bill’s intent. In recent times, it is often referred to simply as the Salisbury Convention.
In the 2017 general election, the Conservative Party won the largest number of seats, but did not secure an overall majority in the House of Commons. This has given rise to questions about whether or how the Salisbury Convention would apply in the case of a minority government that has failed to secure an electoral mandate for its manifesto. Differing views have been expressed amongst politicians and academics on this point. Mark Elliott, Professor of Public Law at the University of Cambridge, has suggested that “the governing criterion is ultimately what members of the relevant political community think”. Lord Thomas of Gresford, the Liberal Democrats’ Shadow Attorney General, has already indicated his view that the Salisbury Convention does not apply to bills put forward by a minority government or under a confidence and supply arrangement.
Similar questions about the applicability of the Salisbury Convention arose after the 2010 general election which also produced a hung parliament. When the Conservatives and Liberal Democrats formed a coalition government, there were debates about whether the Salisbury Convention applied, since the two parties had campaigned on different manifestos, and the coalition agreement in which they set out their programme for government was not drawn up until after the election. While the Government initially asserted that the Convention still held, in 2011 the Minister for Political and Constitutional Reform acknowledged that “with the advent of a coalition government […] the Salisbury-Addison Convention does not operate in the same way, if at all”. During the period of the Coalition Government, there were attempts on three occasions to block a government bill at second reading in the House of Lords, all of which failed.