The House of Lords could lose its bishops under plans being considered by the Prime Minister.
Gordon Brown is looking at proposals for a radical reworking of the upper chamber of Parliament as part of wider plans for constitutional change.
Justice Secretary Jack Straw is expected to publish details of the proposals before the House of Commons begins its summer break next month.
One option under review would make the upper house entirely elected, abolishing the places currently held for the 26 most senior Church of England bishops.
Critics fear that secularists could use this change to force a church and state split.
Another option being considered could see 80 per cent of the House being elected, with 20 per cent reserved for appointed members and others such as bishops.
This option is favoured by those who believe the upper house benefits from the expertise of appointed members with experience in many different fields.
A partially-elected house is likely to gain the backing of the Conservatives. The Party leader, David Cameron, recently expressed his support for an upper house where two thirds of members are directly elected.
Last year immigration minister, Phil Woolas, sparked controversy by saying that a split between church and state was inevitable.
This prompted a response from the Rt Revd Christopher Herbert (then Bishop of St Albans), who wrote an article for The Times in defence of the current system.
He argued: “First of all, it is misinformation to say that Britain is a secular society. The evidence that we have from the 2001 census is that more than 72 per cent of people under no pressure whatsoever described themselves as Christian and 6 per cent as belonging to another faith.
“Even roughly one in five worship monthly – a huge number – but the Church of England exists not simply for those who come to church, but for every single person who lives within our parish system.”
He continued: “The Church creates webs of relationships across our country, which are very strong and very important for community cohesion (to pick up government language). If the Church was disestablished the loss would be enormous.
“Our society and the Church have evolved together. It’s part of the tradition of the country and I’m not sure what’s so bad about tradition in that sense.
“In the 21st century, it’s not about power – it’s about the desire of the Church to serve every community and where necessary to challenge it, comfort it and say when things have gone wrong.”