The Parliament Acts of 1911 and 1949 restrict the power of the House of Lords to block legislation.
Under the acts, those bills which have been approved by the House of Commons can be given Royal Assent without passing through the House of Lords in certain circumstances.
If the Lords refuse to agree to a bill which has already been approved by the Commons, the government can pass the Bill into law, after a delay of one year, without the Lords' agreement.
The powers granted in the Parliament Acts were used to force through the War Crimes Act in 1991, the Sexual Offences (Amendment) Act in 2000, and the Hunting Act 2004.
The Parliament Acts also provide that Money Bills, such as the Finance Bill, do not require the Lords' consent before gaining Royal Assent. The Parliament Acts do not apply to bills introduced by Lords, or bills to extend the life of Parliament beyond five years.