Labour MP Eric Joyce has been charged with assault following a late night fracas at a House of Commons bar in which a Tory rival was allegedly head-butted.
The former soldier, 51, was arrested on Wednesday amid claims Conservative Stuart Andrew had been attacked shortly before closing in the Strangers Bar, Parliament's pub for MPs.
Joyce, who has been suspended from the Labour party in the wake of the incident, was released on police bail last night after spending around 24 hours in custody.
Scotland Yard later confirmed the politician had been charged with three counts of common assault and will appear on bail at West London Magistrates' Court next month.
Joyce, the MP for Falkirk, was seen being driven away from the rear of Belgravia Police Station in central London in the back of a dark hatchback car at around 11.20pm following his release.
He was wearing a white shirt and dark suit and appeared pale and unshaven.
A Scotland Yard spokesman said: "Eric Joyce, aged 51, an MP of Union Street, Bo'ness, West Lothian has been charged with three counts of common assault following an incident within the House of Commons on Wednesday, 22 February.
"He will appear on bail at West London Magistrates' Court on 7 March."
Police said they were called to a disturbance at the Palace of Westminster at around 10.50pm on Wednesday before making the arrest.
Mr Andrew, MP for Pudsey, had no visible cuts or bruises yesterday and responded to concerns about his welfare on Twitter by writing: "I'm ok."
Labour suspended Joyce from the party pending the results of the police investigation, branding the incident "extremely serious", though he remains an MP.
Following his arrest a Labour Party spokesman said: "This is an extremely serious incident. We have suspended Eric Joyce pending the results of the police investigation."
Speculation about the incident has been rife in Westminster but Commons Speaker John Bercow yesterday thwarted any attempt to raise the matter in the chamber by issuing a stern warning at the start of proceedings.
He told MPs: "I take this matter very seriously, as do the House authorities. I would ask that no further reference should be made to these reports in the Chamber."
Joyce, MP for Falkirk since December 2000, served in the Army Education Corps before pursuing a career in politics.
Tory backbencher Andrew Percy, one of those believed to have been caught up in the fracas, tweeted this morning that he felt "sorry" for Joyce.
Insisting he was "fine" after the incident, the Brigg and Goole MP added: "Tbh, I sort of feel sorry for him. People in a good place don't act like that. That's all I'll tweet on it!"