Peers are voting on a Tory bid to delay the ratification of the EU Treaty for four months, in the wake of its rejection in an Irish referendum.
The government has defeated a last ditch attempt to delay the ratification of the EU Treaty for four months.
Peers are due to give the bill its third reading - the final Parliamentary hurdle to the treaty's ratification.
Conservative peers had pressed for the ratification process to be postponed until the response of EU leaders to the Irish referendum "No" vote was clear.
The Tories say "changed circumstances" mean a delay is appropriate but critics say it is a "wrecking amendment" from a party which opposes the treaty.
But the move by Tory foreign affairs spokesman Lord Howell of Guildford was defeated by 277 votes to 184.
During the debate four protesters were removed from the chamber.
The bill to ratify the treaty is expected to complete its Parliamentary passage later on Wednesday.
A woman was removed after demanding a referendum on the treaty and shouting: "It is a democracy". She was followed by three more protesters, at intervals, demanding a referendum.
'Technically dead'
The EU (Amendment) Bill could be given Royal Assent on Thursday and the government would then take deposit documents known as "instruments of ratification" in Rome.
But the Lisbon treaty will not come into force until all 27 countries have also deposited their instruments of ratification.
If one or more countries does not ratify the treaty, a future British government could withdraw from it.
Conservative peer Lord Howell tabled the amendment to delay the third reading of the bill until 20 October in the light of the Irish vote.
Earlier Lord Howell told BBC News: "The thing needs thinking about and it seems a bit silly to close it all down now and ratify a treaty which is technically dead."
'Insult to Parliament'
Among those interrupted by protesters was Labour former minister Baroness Symons, as she made a pro-EU speech. Speaking over the shouting she said moves to delay the third reading were an effort to delay the "properly constitutional legislative process" of Parliament.
Crossbencher Lord Neill, referring to the Irish referendum, told peers the "bill has been crippled by the shot that has gone through it".
And the Conservative peer Lord King said it had become "a bit of a muddle" and peers could not know what would happen in an upcoming EU Council meeting in Brussels this week.
This amendment is being put forward ... as a wrecking amendment to do tonight what they have failed to do throughout this Parliamentary process Lord AshdownLiberal Democrats
He asked if they were expected to do "a third reading on a corpse" adding: "It seems to me an insult to Parliament."
But Baroness Symonds said the Conservatives had "freely admitted they don't like the treaty" and the amendment was "a pretext": "It's a last-ditch attempt to block or delay the bill."
Several people, including the Labour former leader Neil Kinnock, spoke against the amendment, saying that ratifying the treaty would strengthen the prime minister's position at the EU Council meeting.
'No purpose'
Lord Kinnock said delaying the vote would put the UK "on the sidelines", while ratifying it would put Mr Brown in a stronger position to "safeguard the interests of Ireland".
And the former leader of the Liberal Democrats, Lord Ashdown, warned: "This amendment is being put forward ... as a wrecking amendment to do tonight what they have failed to do throughout this Parliamentary process .... There is no purpose in delaying it."
But former SDP leader Lord Owen said he thought it would be better to delay the third reading until after the Brussels summit this week.
EU foreign ministers have said member countries which have not yet ratified the treaty should still press ahead.
Earlier, Conservative leader David Cameron urged Prime Minister Gordon Brown to declare the EU treaty "dead".
