Falkirk MP Eric Joyce has been bailed by detectives investigating an alleged late-night brawl at a House of Commons bar.
Mr Joyce, 52, was arrested on suspicion of assault, and re-arrested on suspicion of actual bodily harm while in custody at Belgravia police station, central London. He left in a waiting taxi shortly after being released.
Serjeant at Arms Lawrence Ward - who is responsible for security and keeping order in the Commons - has confirmed that the Independent MP would be subject to an indefinite alcohol ban in parliamentary bars.
A Metropolitan Police spokesman said: "A man aged in his 50s, arrested on Thursday 14 March on suspicion of assault in connection with a disturbance in a bar within the House of Commons, has been bailed to return to a central London police station on a date in late March. He was further arrested while in custody on suspicion of actual bodily harm."
Mr Joyce left the police station by a back exit, accompanied by two women. Before he got into the black cab, he told members of the press he had not been charged, adding that he had no further comment to make.
Mr Joyce was previously fined by a court and given a three-month ban on entering pubs and bars following an incident in a Commons bar last February, when he punched and head-butted fellow MPs. Asked about the alleged incident during a press conference in Brussels, Prime Minister David Cameron said: "This is going to have to be properly looked at and I'm sure that the authorities both inside and outside of the House are more than capable of doing that."
It is understood Mr Joyce was involved in an altercation at the Commons Sports and Social Club bar after apparently being told he could not take a glass with him when he went to a smoking area outside.
Witness Tony Grew, a journalist from the PoliticsHome website, told ITV the incident happened during a karaoke night in the bar, which was packed with about 150 people. He said Mr Joyce entered the room "obviously agitated" and pushed his way forward to the bar. When he followed him out of the bar he saw Mr Joyce on the ground "wrestling with two police officers".
Mr Joyce resigned from the Labour Party after head-butting Tory rivals Stuart Andrew and Ben Maney in a previous incident in a Commons bar last February. He also punched Tory councillor Luke Mackenzie and Labour whip Phillip Wilson and swore at police on that occasion. The former soldier walked away from Westminster Magistrates' Court with a fine and pub banning order after admitting four counts of common assault in relation to that incident. He was fined £3,000 and ordered to pay £1,400 to victims after he entered early guilty pleas.
Mr Joyce was also given a 12-month community order - banning him from entering pubs and licensed premises for three months - and imposed with a curfew order from Friday to Sunday. After that hearing, Mr Joyce admitted he was lucky to avoid jail and said he was "deeply apologetic".