The House of Lords could be radically reformed after a shock vote by MPs.

They voted for a 100% elected House of Lords, stunning many at Westminster who expected them to retain a proportion of appointed peers.

All peers are appointed, apart from 92 hereditary peers who survived the first phase of Lords reform during Tony Blair's first term in office.

The vote saw MPs vote by a majority of 113 for a complete change, potentially paving the way for one of the most significant constitutional changes in Britain's history.

The surprise vote prompted claims it had been engineered by opponents of change, hoping it would kill the momentum for reform by provoking resistance in the Lords.

But Leader of the Commons Jack Straw, who is in charge of the reform process, made it clear he would give great weight to the Commons result when drawing up a draft Bill, expected this year.

Mr Straw said he would reconvene a cross-party working group to discuss the way forward following next week's vote in the House of Lords, which is expected to support only a minimal element, at most, of directly-elected peers.

Both the Commons and Lords votes are advisory and not binding on the Government.

But Mr Straw claimed he now had "not just a mandate, but an obligation, to deliver what the Commons has said".

Voting on a series of options following a two-day debate, MPs also backed a proposal for an 80%-elected upper house, but by a smaller majority of 38.

They rejected any smaller proportion of elected members - including the 50-50 split between appointed and elected peers favoured by Mr Straw and Prime Minister Tony Blair.

But they also voted down a proposal to abolish the second chamber altogether and leave the House of Commons sitting alone at Westminster.

By an overwhelming margin of 391 to 111, MPs voted to remove the last 92 hereditary peers from Parliament.

Despite last night's conclusive 337 to 224 vote in favour of a fully-elected upper house - which was greeted by cheers in the packed Commons chamber - reform of the Lords is far from a done deal.

Much depends on what priority Chancellor Gordon Brown gives it if he takes over as Prime Minister.