Why are conventions still an important part of the UK constitution?

Conventions are customs, that although not legally binding, are usually followed. Conventions play a major role in the UK constitution, but are often changing and developing. Sometimes, new conventions emerge whilst others die away, or are codified by the passing of a Statute Law.

There are a number of conventions that are essential to the functioning of the UK political system and serve very important purposes. A good example of this that the supremacy of  the House of Commons is largely ensured via two important conventions:


The Supremacy of the House of Commons is largely outlined by two important conventions.

The House of Lords does not vote against Money Bills – This is an extremely important principle. It guarantees that decisions over the spending of taxpayers money are taken by the elected chamber.

The House of Lords does not vote against anything in the Government’s Manifesto (Salisbury Convention) – This ensures that the wishes of the electorate, reflected in their choosing of a Government, are upheld by Parliament.

(More can be found out about the Salisbury Convention here).


The Denison Convention was named after John Evelyn Denison, the Speaker of the House of Commons from 1857 to 1872.

Other conventions dictate the way Parliament works. An example of this is the Denison Convention. This convention dictates how the Speaker of the House of Commons should vote in the event of a tied vote in the House of Commons. The convention says that the Speaker should always vote with the Status Quo.  For example, the Speaker would vote against any amendments to a bill or against a bill from passing. However, the Speaker is always expected to vote in favour of further debate of any issue.  This convention helps to reinforce the politically neutral position of the Speaker of the House of Commons. The Denison Convention has only been invoked 49 times since 1867 and was last used in 1993 when Betty Boothroyd voted on the Maastricht Treaty.

It is also by convention that the Queen appoints as Prime Minister the person who can best control the ‘confidence of the House of Commons’. This is why it would be unthinkable for a Prime Minister to govern from the House of Lords in the modern day – the last was Lord Salisbury in 1902.

There are many more conventions that exist, but these are just some of the most important.

Alan Lascelles

The Lascelles Principles were named after Alan Lascelles, the Queen’s Private Secretary

Some conventions go out of use, often because the custom they outline has been codified into law or because a law has been passed that means they are no longer relevant. For example, there was previously a Constitutional Convention called the Lascelles Principles. This convention stated that the monarch could refuse a request from the Prime Minister to dissolve Parliament (and therefore call a new election) if:

  1. The existing Parliament was still capable of doing its job.
  2. If a General Election would hurt the national economy.
  3. If a Government could be formed without a General Election.

However, in 2011 Parliament passed the Fixed-Term Parliaments Act which removed the power of the Prime Minister to call an early election. An early election can now only be called via a vote in Parliament and the Lascelles Principles are therefore defunct.

An example of a new convention emerging is the Carswell Convention. In 2014 Douglas Carswell decided to ‘cross the floor’ and leave the Conservative Party in order to join UKIP. However, after doing so Carswell resigned as an MP and forced a by-election, which he then stood for as the UKIP candidate. Although he was not legally required to do this, he did so because he believed it to be important that the voters had a say on his decision. Carswell went onto win the subsequent by-election, and sat as a Conservative MP.

D Carswell

Former Conservative and UKIP MP, Douglas Carswell, now has a constitutional convention named after hm.

By taking this action, Carswell created a precedent that it seemed others should follow. Later in 2014, when Mark Reckless also left the Conservatives for UKIP, he resigned to force a by-election. The Carswell Convention had clearly been established as an accepted convention in the UK.

It seems strange that conventions can play such a big role in a modern representative democracy. However, it is a result of the nature of the uncodified nature of the UK constitution. In the United States the constitution outlines the powers of the President, the roles of Congress and various other constitutional issues which in the UK are governed by convention. Yet, despite conventions not being legally enforceable, they are rarely broken. When they have been, Parliament has taken action to fix the situation. The most famous example of this occurred between 1909 and 1911.

In 1909 the House of Lords voted against Lloyd George’s ‘Peoples Budget’. By doing this, they ignored the constitutional convention that the Lords does not vote against money bills. In response to this, Parliament passed the Parliament Act (1911) which removed the power of the House of Lords to block legislation.

There have been further occasions when conventions have been ignored, or at least not strictly followed. For example, in 2015 when the House of Lords voted against cuts to Tax Credits, leading to the Conservative Government accusing the House of Lords of causing a constitutional crisis. Yet, no crisis emerged and conventions have generally been followed.

In the future it is likely that conventions will become less important as the British constitution becomes increasingly codified. However, they are, and will remain, an important source of the UK constitution.

2 thoughts on “Why are conventions still an important part of the UK constitution?

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

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