MP Eric Joyce has been arrested after an altercation at a House of Commons bar - a year after being convicted of a previous disturbance.
The independent MP for Falkirk, who was formerly affiliated to Labour, was detained following an incident in the Sports and Social Club bar inside the Palace of Westminster.
Witnesses described seeing the 52-year-old "wrestling" with two police officers before he was arrested. It is believed that the altercation started after Joyce objected to a request for him not to take his drink outside the bar during a packed karaoke night.
A Metropolitan Police spokesman said: "Police were called to reports of a disturbance at a bar within the House of Commons.
"Officers attended and a man in his 50s was arrested in connection with this incident.
"He remains in custody and inquiries continue."
The incident was witnessed by politicshome.com parliamentary editor Tony Grew. He described how Joyce "had one of the officers in an armlock".
"I can vividly remember a policeman's hat rolling on the ground towards me as I was watching," he added.
Joyce's arrest comes just over a year after he was fined £3,000 and banned from pubs for three months after pleading guilty to four counts of assault in the House of Commons Stranger's bar.
He was given a 12-month community order, including a Friday-to-Sunday curfew, after headbutting Tory MP Stuart Andrew and attacking three other politicians including Labour whip Phil Wilson.
Joyce, who accepted he was "hammered" on red wine that night, was reported to have shouted that the bar "was full of f*****g Tories" before launching the attack.
Following the brawl, the former soldier resigned from the Labour party and said he would not stand in the next election.