JOIN USBeds had been laid out and dormatories marked for different sexes and political parties as the House of Elders debated the issue of reforming UK's voting system.
Free tea and biscuits were served all night-long, but the Lord's bar downed the shutters at its scheduled closing 2230 hrs GMT. Though, soup and chocolates were at hand from the nearby Bishops sandwich bar.
This was the setting for the first trial of strength of the coalition era between the government and Labour in the House of Lords.
As the House hotly debated the issue, older peers sneaked off to take short snoozes in five rooms set aside, so peers could rest their heads between votes.
With the Leader of the Lords, Lord Strathclyde accusing the opposition Labour party of slowing down the proceedings, the Monday nights sitting was the longest in living memory and went on well into Tuesday morning.
"It was a test of stamina," said 72-year-old peer David Steel. He said in his thirteen years in the House of Lords, he had never known an all night sitting.
"There were lot of very older members and I don't know how they survived," Steel told BBC radio, adding, he found it a struggle.
While all night debates are a regular feature in the House of Commons, it is a rarity in the House of Lords.
The peers held the debate as the voting reform bill needs to become Law by the middle of the February. If they do not, then existing electoral law says there will not be enough time for officials to prepare for the referendum which is scheduled for May 5.