The House of Lords finally rose at 3.04am today, ending the latest in a series of marathon debates on plans to change the voting system and cut the number of MPs.
The adjournment came with shadow justice minister Lord Falconer of Thoroton warning the Government had "absolutely no prospect" of the Parliamentary Voting System and Constituencies Bill reaching the statute book by February 16.
Ministers are determined to stage a referendum on adopting the alternative vote (AV) system for Westminster elections on May 5 and according to the Electoral Commission, the Bill must become law by the February date.
Lord Falconer, a former Lord Chancellor, said his party was "keen to engage in serious negotiations".
Labour peers, who oppose the plan to cut the number of MPs from 650 to 600 arguing it would favour the Conservatives, have repeatedly called for the Bill to be cut in two so the AV part can clear the Lords in time and the rest of it can be discussed further.
But the Government has accused Labour of deliberately holding up the legislation with "filibustering" tactics and Prime Minister David Cameron said yesterday Ed Miliband had "lost control of his party" and he would make no "concessions".
Peers sat throughout the night on Monday and there had been suggestions the same tactic would be used last night by the Government.
Lord Falconer's attempt, just after 2am today, to adjourn the House was defeated by 103 votes to 63, majority 40, but the Government then moved to adjourn the House an hour later.
The 11th day of committee stage debate, which got under way just before 4pm yesterday, ended five hours after the usual 10pm finishing time in the Lords and less than eight hours before the start of the next sitting.
Peers will now return to the committee stage of the Bill issue next week on Monday and Wednesday, when ministers hope it will be concluded.
During last night's debate the Government suffered a defeat as peers voted to prevent the creation of a constituency split between the Isle of Wight and the mainland.
The move by Tory ex-Cabinet minister Lord Fowler, who argued the Bill's plan to stick to strict electoral quotas to determine constituency sizes would inevitably break the unity of the island in Parliamentary terms for the first time since 1832, won the support of 28 Conservative and 14 Lib Dem rebels.
It was the second defeat the Government has suffered on the Bill, which will have to return to the Commons for MPs to consider whether to accept the alterations.
Before Christmas peers voted to allow the referendum on changing the voting system for Westminster elections to the alternative vote (AV) to be held at any point before October 31.
Tetchy relations in the Lords, which were a feature of the debate that lasted from 3.48pm on Monday until 12.51pm on Tuesday, reached a low yesterday evening after Lib Dem Lord Thomas of Gresford moved a motion that cut short debate on an amendment.
His rare procedural device "that the question be now put" - a measure also invoked once on Monday night - was agreed by 229 votes to 188, majority 41.
Labour shadow justice minister Lord Bach moved to adjourn the House in "sadness and also anger" claiming Lord Thomas's procedure had not been used for 20 years before Monday and was an "abuse" of the House.
But he withdrew the move in light of conciliatory speeches and calls for calm from Tory ex-Lord Chancellor Lord Makay of Clashfern and crossbench retired professor of philosophy Baroness O'Neill of Bengrave.
"I certainly greatly regret that we have come to a position where a closure motion has happened on two occasions," Lord Mackay said.
"I certainly hope that there will be no further motions of closure and I also hope that all of us, myself included, will conduct ourselves in a practical way."
He called for a "spirit of real co-operation" and for "some real concessions" from the Government while also noting some debates had lost their "complete adherence to relevance and succinctness".
Lady O'Neill warned the Lords' function of scrutinising legislation was threatened by tactics which amounted to a "filibuster" or a "guillotine".
She added: "The situation we have arrived at, with the double use of the closure motion, is edging us towards a guillotine. If this House has a guillotine, we shall be in the situation where scrutiny is impossible.
"I think scrutiny has become impossible during the course of this Bill. I think it has become impossible in part because of, whether co-ordinated or not, the repetitive and irrelevant comments made in many speeches by noble Lords on the Opposition benches.
"This too, I believe, is an abuse of the procedures of this House. I also believe that the resort to the motion for closure, with its implicit guillotine, is an abuse of the process of this House."
Following the interventions there appeared a more co-operative attitude in debates. In the 10 hours spent debating the Bill nine groups of amendments were considered, compared to just eight groups discussed in Monday night's 21-hour debate and three in the 80-minute debate during Tuesday afternoon's short sitting.
There are a further 49 groups of amendments left to deal with and, after the committee stage is finished, the Bill still has to go through report and third reading stages before it returns to the Commons for MPs to consider amendments introduced in the Lords.
By convention, there are meant to be 14 days between the end of committee and the start of report and three sitting days between the end of report and the start of third reading, although it is possible for those intervals to be cut.