A series of ministers appeared set to defy the prime minister by voting in support of a largely-elected second chamber.

Ministers thought likely to vote against the prime minister included Peter Hain and Patricia Hewitt.

Aides to ministers say the issue is a free vote and dismissed claims that their actions would amount to disloyalty.

Rising stars such as David Miliband, Ben Bradshaw, Yvette Cooper and Douglas Alexander were also set to vote against Blair.

Number 10 indicated Tony Blair took a relaxed view over a potential ministerial rebellion.

The prime minister would be exercising his free vote like any other MP and "votes whenever he has the opportunity to" explained the official spokesman.

Downing Street said the issue was not about personalities, urging the media to "concentrate on the arguments".

The prime minister accepted there was a range of opinion on reform, but stood by his view that the upper house should be representative of the country and not challenge the supremacy of the Commons.

"MPs can make their own mind up, as can peers," said the Number 10 spokesman.

The Commons will first vote on the possible abolition of the Lords and will then vote on alternative options beginning with a fully appointed house.

Following the votes, the joint committee of MPs and peers will then decide on the way forward and report back to parliament.

Number 10 declined to say what outcome it would then like to see.

"We do have to take this one step at a time," said the spokesman.

Ahead of the vote the Campaign for the English Regions published new research demonstrating a massive north-south divide in the Lords.

The group said that London and the South East hugely dominate the second chamber, with 38 per cent of members, at the expense of much of England.

London has 74 MPs but commands 138 peers.