The Salisbury Convention


One of the most important sources of Britain’s uncodified constitution are conventions. These are unwritten agreements which are usually followed. Britain is one of only four countries across the globe with an uncodified constitution. Constitutions from countries in which they are codified are usually formed at the end of a revolutionary period. For example, America’s codified constitution of 1787 was written at the end of the revolutionary war in which America gained independence from Britain. Another example is Russia which implemented a codified constitution in 1993, after the fall of Communism. Unlike these countries, Britain has not had a revolution since the age of enlightenment, during which liberal democracy and constitutionalism became engrained in western thought. Instead, rather than being revolutionary, the UK constitution is evolutionary – more layers have been added through time, rather than undergoing a fundamental restructuring.

Most codified constitutions seek to remove conventions as far as possible – they are often seen as lacking the security of entrenched elements of a constitution. However, in Britain they retain an extremely important role. In fact, in recent years new conventions have emerged:

Carswell Convention – In 2014 the Conservative MP Douglas Carswell resigned the Conservative Whip and joined UKIP. Although constitutionally he was not obliged to do so, he also resigned as an MP – forcing a by-election in his Clacton constituency. He ran in this by-election and won, becoming UKIP’s first elected MP. In September 2014, Mark Reckless MP also left the Conservatives to join UKIP – again resigning to force a by-election. It is now accepted that an MP leaving a party to join another should resign and force a by-election, ensuring that the electorate have a say on this decision. This notion is informally known as the ‘Carswell Convention’.


Former Conservative and UKIP MP now has a convention named after him


Mark Reckless followed Douglas Carswell in leaving the Conservatives for UKIP and resigning, forcing a by-election.

Parliamentary Approval for Military Action Convention – One of the Prime Minister’s Royal Prerogative Powers is the declaration of war. However, increasingly this has become to be seen as something Parliament should have a say other. This started in 2003, when Tony Blair held a parliamentary vote over Britain’s involvement in the war in Iraq. Since this, other votes have been held over military action – including two votes over the authorization for British Air Force bombing in Syria.


In November 2015 Labour Leader Jeremy Corbyn gave his party a ‘Free Vote’ over the issue of Syrian Airstrikes

Despite these new conventions, there are others that have been around for an extremely long period and remain very important. One example of this is the Salisbury Convention, which is sometimes called the Salisbury-Addison Convention. Although the Parliament Act (1911) severely limited the power of the House of Lords by removing its ability to block legislation, is still remained a major obstacle for the government to overcome. In particular, whilst Labour formed its first government under Ramsay MacDonald between 1929-1931, the Conservative dominated House of Lords continued to frustrate their agenda.

Ramsay MacDonald

Between 1929 and 1931 Ramsay MacDonald was Labour’s first Prime Minister

In 1945 the Labour Government of Clement Attlee won a landslide majority of 145 seats. However, in the House of Lords only 16 of 761 were Labour members. This meant that despite the Labour Party having a clear electoral mandate, the House of Lords could block the Government’s agenda. At this point an important agreement was reached between Clement Attlee’s Labour Government and Conservative Members of the House of Lords, Salisbury and Addision. They agreed that it was undemocratic for the unelected House of Lords to stop the elected government from fulfilling the promises that Labour had made to the people in its election manifesto.

The convention agreed was that:

  • Any bill put forward by the Government that was in the governing party’s manifesto would not be voted against by the House of Lords
  • Allows amendment to be placed on a Government bill, but not simply in order to ‘wreck the bill’

The Salisbury Convention has been largely respected ever since. However, there were some question marks raised of it between 2010 and 2015. In the 2010 General Election no party won a majority. Instead, a Coalition Government was formed by the Conservative Party and the Liberal Democrats. To agree to their coalition, they put in place a ‘Coalition Agreement’. This was formed by amalgamating their constitutions. This meant that technically the manifesto of the governing parties had not been fully endorsed by the electorate. During the coalition government the House of Lords inflicted a number of defeats on the Government, some which may previously have been prevented by the Salisbury Convention.

3 thoughts on “The Salisbury Convention

  1. Pingback: Why are conventions still an important part of the UK constitution? | Politics Teaching Website (Launching in September 2018)

  2. Pingback: How effectively can the House of Lords scrutinise the Executive? | Politics Teaching

  3. Pingback: How effectively can the House of Lords scrutinise the Executive? | Politics Teaching

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