After more than 20 hours of continuous voting, the Conservatives have ended their filibuster-like tit-for-tat tactics in the House of Commons.

The overnight vote was in retaliation after the Liberals voted down the Conservatives' motion to have the prime minister's national security adviser testify in front of a committee about the Jaspal Atwal affair. "This has been a very, very long day," said Conservative House leader Candice Bergen just before MPs were given the OK to leave the floor Friday afternoon. MPs have been voting on 250 motions since around dinner time on Thursday, which followed a full day of parliamentary work including question period. The Conservatives had threatened to keep MPs in the House into the weekend, but they withdrew their amendment just before 3 p.m. ET on Friday. The House was ruling on fiscal estimates, so every vote is a vote of confidence, keeping Liberal MPs close to their seats. A loss of confidence could have triggered an election.

But that doesn't mean they always had to be paying attention. Some MPs brought in books, magazine and iPads to keep themselves awake. One rookie Liberal MP was caught dancing to Lionel Richie's All Night Long while Heritage Minister Melanie Joly and other cabinet colleagues performed YMCA.

Conservatives wasting time: PM

Conservatives still maintain the disruption was warranted, given the government's refusal to let Daniel Jean testify at the national security committee about the briefing he gave journalists during Trudeau's India trip.

Quebec Liberal MP Remi Masse sings and dance's to Richie's All Night Long late Thursday night in the House of Commons 0:48

Jean suggested to reporters covering Trudeau's trouble-plagued trip last month that rogue factions in the Indian government had sabotaged the prime minister's visit.

That included the embarrassing revelation that Atwal — a one-time Canadian Sikh separatist extremist convicted of attempting to murder an Indian minister during a visit to Vancouver Island in 1986 — had been invited to two events with the prime minister during his India sojourn. The revelation came just as Trudeau was attempting to convince Indian officials that his government supports a united India and does not condone violent extremism.

"We need the same rights that journalists had," said Conservative foreign affairs critic Erin O'Toole said Thursday.

As the marathon session wound down, Trudeau held a Facebook live to call out the Conservatives

"Every minute of Conservative stunts and stalling wastes time, keeps us from debating common sense gun control, and keeps MPs from meeting with you in their ridings," he posted online.

The Privy Council Office said the government has offered a briefing on the India trip to Conservative Leader Andrew Scheer, something he categorically denied while taking reporters' questions in Toronto.

"Our indication was that the Prime Minister's Office was checking with their legal counsel to see if it would be possible and they were going to get back to us," he said.

"I'd be happy to accept a briefing from the national security adviser on this issue as long as it includes members of Parliament, members of Parliament that are there to represent the elected people to find out what exactly happened."

Minister of Finance Bill Morneau speaks to reporters before heading into the House of Commons on Parliament Hill during a marathon voting session in Ottawa on Friday, March 23, 2018. (Justin Tang/Canadian Press)

The marathon vote will result in a hefty overtime bill for the Commons, since its services must be available whenever the chamber is sitting.

Those services include security, cafeteria, shuttle buses, messengers, translation, transcription, printing, maintenance and tech support.

Travel disruption

After about three hours of voting, Liberal MP Rob Oliphant asked that the Commons mobilize additional staff so that the young pages in the chamber would not be "run off their feet all night."

Back in 2011, when the NDP conducted a 58-hour filibuster against the then-Conservative government, Tory MP Candice Bergen — now the party's House leader — pegged the cost of keeping the Commons running at $50,000 an hour, although her own government disputed that figure.

Parliamentary secretaries then cabinet ministers perform the dance moves associated with the Village People's YMCA Friday morning 0:35

Whatever the overtime costs for Commons employees, they don't include the cost of rearranging travel plans. Many MPs, particularly from far-flung parts of the country, normally return to their ridings on Thursday nights. Cabinet ministers also tend to fan out across the country on Fridays to make announcements or attend events.

Transport Minister Marc Garneau had to cancel his plans to travel Friday to Lac Megantic, Que. — site of the 2013 rail disaster that levelled half the downtown area — where he was scheduled to discuss rail safety with the Quebec Federation of Municipalities.

'A human shield'

Trudeau has stood by his national security adviser, saying Jean is a professional, non-partisan, veteran public servant who only says what he knows to be true.

But the Conservatives maintain Jean was used by the PMO to deflect attention from a public relations disaster.

Jaspal Atwal — a one-time Canadian Sikh separatist extremist convicted of attempted murder— had been invited to two events with the prime minister during a recent trip to India. (Jonathan Hayward/Canadian Press)

"When the prime minister uses a senior and respected civil servant as a human shield to get out of a bad political scandal, that's terrible," said O'Toole.

He questioned how one could argue that Indian factions could have been responsible when a Liberal backbencher, Randeep Sarai, has taken responsibility for getting Atwal on the guest lists and Foreign Affairs Minister Chrystia Freeland has called the incident an "honest mistake."

"Both of these scenarios can't be true and the fact they brought up the India conspiracy theory also is a blight on a good relationship with an important country," O'Toole said.