Both the Parliament Act and the Salisbury Convention are ways of regulating the relationship between the UK House of Lords and the UK House of Commons.
The Parliament Act regulate the relationship between the House of Lords and the House of Commons.
The House of Lords, until the early 20th century had equal powers to the House of Commons. Except it was a convention that the Lords would not overrule the Commons on issues related to taxation and public spending.
In 1911, a major conflict between the Conservative majority in the Lords and the Liberal Government led to the passing of the Parliament Act.
This allowed the Commons to overrule a Lords veto over legislation by voting it down in two successive sessions of Parliament.
It also made it illegal for the Lords to delay taxation and public spending legislation for more than one month.
In 1949, the Labour Government reduced the delay over legislation to one session.
In practise Governments have hardly ever had to use the Parliament Acts as the Lords have looked to avoid major conflicts over legislation.
Since 2000, it has been used to overrule the Lords on the age of consent for gay men and fox hunting.
Although the House of Lords had lost its absolute veto in 1911 it could still wreck a Government’s legislative programme. It could delay consideration of Bills and pass large number of amendments that the Commons would have to reverse.
The Conservatives were in power for most of the time between 1911 and 1945 and so the Conservative majority in the Lords did not oppose Conservative legislation.
When Labour won its huge majority in the Commons in 1945, the Conservative leader of the Lords, Lord Salisbury, did not want constant conflict and so made an agreement with the Labour leader of the Lords, Lord Addison.
The Salisbury Convention, as it became known, proposed that the Lords would not defeat or delay any legislation that carried out a proposal that was in the winning party’s manifesto.
The Coalition Agreement which replaced the manifestos of the two Coalition parties led to new debate about the Convention. For example, the Lords rejected proposals in the Coalition Agreement to create elected police commissioners.
