David Cameron is demanding changes to plans to elect the House of Lords in an attempt to avert what threatens to be a huge Tory rebellion.
Elected peers will have bigger constituencies, non-partisan candidates with real-world expertise will be highlighted on ballot papers, and the supremacy of the Commons over the Lords will be enshrined in law, as part of the Prime Minister's amendments.
The proposal to replace appointed and hereditary peers with an 80 per cent elected Upper House threatens to become the biggest challenge to coalition unity. Tensions between the two parties are running high after rows over the future of the Culture Secretary, Jeremy Hunt, and plans to abolish GCSEs. Some Tory backbenchers see defeating Nick Clegg's legislation as "payback". The final draft of the House of Lords (Amendment) Bill will be agreed by the Cabinet on Tuesday, and made public later in the week. Mr Clegg is expected to lead the first Commons debate on the Bill in the second week of July.
At present, there are 816 members of the Lords, of whom 698 were appointed by political parties, 92 are hereditary peers and 26 are archbishops. Under the coalition plan, the total number would cut by more than half, with at least 80 per cent of peers being elected. The first tranche of elected "senators" would be elected in 2015, to serve a single term of 15 years. Two more would be elected in 2020 and 2025.
As many as 100 Tory MPs are threatening to rebel. But No 10 hopes the prospect of a government reshuffle, which could come any time between now and September, will persuade those hoping for promotion to toe the line. It knows a large rebellion would damage Mr Cameron's authority.
The Prime Minister has insisted the electoral map for elected peers be redrawn, to stop them challenging the supremacy of MPs. Instead of small electoral districts, with between five and seven members, as proposed by a cross-party committee, members of the house would be elected to represent each of the nine English regions, Scotland, Wales and Northern Ireland.
Mr Cameron has rejected calls for a referendum on the changes, accepting Mr Clegg's argument that reform was promised in the 2010 general election manifestoes of both governing parties. But Sadiq Khan, Labour's justice spokesman, insisted "fundamental changes to our constitution should be put to the people in a referendum". He added: "They are denying the public a vote on the very fabric of how our country is to be run."
Last week, a report by Lord Lipsey, the economist, suggested the changes would cost £484m to implement.
History Of Lords Reform
1911 Parliament Act gives Commons power to overrule Lords.
1958 The first appointed peers join those who inherit their title.
1999 Tony Blair secures deal to remove most of the hereditary peers, leaving just 92.
2000 Royal Commission recommends a smaller house of 550 members, with either 65, 87 or 195 elected.
2003 MPs and peers vote on different levels of elected peers between 0 and 100 per cent. The Commons fails to agree an option, and the Lords supports wholly elected Upper House.
2007 In a fresh round of votes, the largest majority in the Commons is for a 100 per cent elected chamber. The Lords vote overwhelmingly for wholly appointed chamber.
2010 At the general election, Labour promises a fully elected Lords, after a referendum. The Conservatives say they will "work to build a consensus for a mainly elected second chamber". The Lib Dems pledge a smaller, fully elected second chamber. 2012 House of Lords (Amendment) Bill.