Peers have rejected plans for a fully elected House of Lords - setting them on a clear collision course with MPs.
Lords voted on reform after two days of debate
Last week MPs voted in favour of 80% or all members of a reformed second chamber being elected in the future.
But a crowded House of Lords instead voted to keep a fully appointed house, voting down other options for reform.
Votes are not binding but the division between MPs and peers suggests any attempt to draw up a reform bill will meet months of parliamentary gridlock.
About 500 peers, including former prime minister Margaret Thatcher, showed up for the vote on Wednesday, crowding the red leather benches and leaving some crouching on the steps of the throne.
Peers backed plans to remain as a fully appointed house by 361 votes to 121 - a majority of 240.
As the votes continued, they rejected each of six other combinations of elected and appointed peers, including the 50/50 split favoured by the prime minister and Commons leader Jack Straw.
100% appointed: Approved 361 to 121
20% elected 80% appointed: Defeated without vote
40% elected 60% appointed: Defeated without vote
50%/50%: Defeated 46 to 409
60% elected 40% appointed: Defeated 45 to 392
80% elected 20% appointed: Defeated 114 to 336
100% elected: Defeated 122 to 326
Lib Dem peer Lord McNally criticised the result saying: "A veto on constitutional reform by the House of Lords is not acceptable. It is now up to the House of Commons to assert its primacy.
"The Liberal Democrats' 100-year-old commitment to an elected House of Lords remains intact."
But during two days of debate, others argued against tampering with an institution which had worked well for centuries and had public support.
Labour's former Lord Chancellor Lord Irvine said the MPs' backing for a fully elected House of Lords was "an error of historic proportions".
And former Commons Speaker Baroness Boothroyd said: "The future of our parliament is at risk if we upset the balance between the two Houses that has served this country well."
The votes are not binding - but will be considered by ministers if a reform bill is to be drawn up.
In theory the Commons could force through changes against the wishes of the House of Lords, but that would be controversial and take up a great deal of Parliamentary time.
The issue then would be whether Gordon Brown, or whoever succeeds Tony Blair as prime minister, sees the reform as a high enough priority to justify the amount of government time it would be likely to take up.
Commons Leader Jack Straw, who proposed the plans, is battling to reach a compromise with the widest possible backing.
There has been some speculation that some MPs who voted for a 100% elected House of Lords last week did so to scupper plans by ensuring an option unacceptable to either the government or peers was chosen.