The Salisbury Convention is a convention that works to ensure that the unelected and appointed House of Lords, cannot unduly block the legislative programme of a democratically elected government in the House of Commons.
The convention (sometimes called the ‘Salisbury doctrine’) states that the Lords will not vote down a Bill that seeks to enact a manifesto pledge on which a government was elected.
In this way, the Lords submits to the popular mandate of the Government of the day, regardless of its party.
After the removal of the hereditary peers in 1999, there was been some discussion as to whether the convention should hold. Some argued that the legitimacy of the Upper House was enhanced by the 1999 Act, allowing it a wider veto, while others maintain that, without elections to the Upper House, the convention should remain unchanged.  This falls under the wider debate around House of Lords Reform.
The large body of cross bench peers, not to mention the 26 places reserved for Bishops from the Church of England, means that no government is likely to ever posses a majority in the House of Lords.
For example, in 2020, the Conservative Party had just 263 of the 805 Peers in the House of Lords. The Labour Party had just 183 sitting peers.
