Eric Joyce, a Labour MP, has been suspended by his party and charged with three counts of common assault following an incident in which he is alleged to have head-butted a Conservative MP during a late-night fracas in a House of Commons bar.
The 51-year-old MP for Falkirk was released late last night from Belgravia Police Station, where he was questioned after Stuart Andrew, Tory MP for Pudsey, told police he wanted to press charges for assault. A Scotland Yard spokesman said Mr Joyce will appear on bail at West London Magistrates' Court on 7 March.
An MP said breathlessly: "It was like the Wild West."
Inevitably, there were differing accounts about what happened in the wood-panelled Stranger's Bar at about 10.50pm on Wednesday.
Some people said that, after entering the bar at about 10pm, he was singing songs and another MP asked him to turn down the volume a little.
Witnesses heard Mr Joyce shout: "There are too many f***ing Tories in here." Then Mr Andrew, having a quiet pint of beer, was allegedly head-butted by the Falkirk MP. One colleague described him as someone who happened to be sitting in "the wrong place at the wrong time". Several MPs tried to calm things down. Phil Wilson, Tony Blair's mild-mannered successor in Sedgefield and a Labour whip, was apparently punched and got a blood-soaked shirt for his pains.
At one point, Mr Joyce allegedly head-butted Mr Andrew. Others who intervened included Tory Alec Shelbrooke, MP for Elmet & Rothwell. But the heroine of the hour was Jackie Doyle-Price, Tory MP for Thurrock, who was more successful than her male counterparts in cooling the situation down.
Police were called and it took five security officers to bring the incident to an end. Mr Joyce was handcuffed and was reportedly still struggling as he was led away. A glass window in a door along the corridor was broken.
Yesterday, bar staff on duty at the time were asked to attend the police station for questioning, while officers interviewed some MPs in their offices. John Bercow, the Commons Speaker, told MPs: "I have been informed by the Serjeant at Arms that the honourable member for Falkirk has been detained in police custody. The matter is being investigated. I take this matter very seriously, as do the House authorities."
Scotland Yard confirmed it was still questioning a man over the alleged assault. A spokesman said: "The man remains in custody at a central London police station."
The Labour Party said: "This is an extremely serious incident. We have suspended Eric Joyce pending the results of the police investigation."
Traditionally, the Strangers Bar was regarded as the rowdiest at the Palace of Westminster, although it sometimes faced stiff competition from the Press Gallery. Its most common nickname is "The Stranglers", but it used to be widely known as "The Kremlin" for being mainly used by Labour MPs.
They downed pints of Newcastle-brewed Federation Bitter, while the Tories sipped gin and tonic or brandy in the more refined atmosphere of the Smoking Room.
However, some of the large intake of Tory MPs at the 2010 election now visit the Strangers Bar regularly – to the irritation of some Labour MPs.
The bar is for MPs, who are allowed to invite outsiders. Guests are not supposed to buy drinks – officially, at least.
The astonishing incident of Wednesday is a throwback to the culture which largely disappeared when the Blair Government brought in family-friendly Commons hours.
Late-night sittings are now rare and business ends at 7pm on most Wednesdays and Thursdays.
Profile: Blair loyalist seemed to have major issues
When Tony Blair was Prime Minister, Eric Joyce was regarded by the Labour high command as the ultimate loyalist. He was prepared to defend the most difficult decisions, such as the Iraq war, and was trusted to bat on sticky wickets such as BBC2's Newsnight programme.
He appeared less happy after Gordon Brown succeeded Mr Blair in 2007. There were persistent rumours that he was going to resign his post as a parliamentary private secretary, the lowest rung on the government ladder, because he was disillusioned with the Brown administration. That came to nothing but he eventually resigned as aide to the Defence Secretary, Bob Ainsworth, because of his "concerns" over the strategy in Afghanistan.
After the 2010 election, Mr Joyce served briefly as a Northern Ireland spokesman but resigned later that year when he lost his driving licence for failing to provide a breath test. There were reports of marriage problems and in a blog about the death of a friend in 2010, he suggested that he was trying to exorcise his "demons". Earlier this week, he tweeted: "OK, who's the hardest boxing correspondent in the country? There's only one way to find out."
Born in Perth, Mr Joyce signed up as a private in the Black Watch when he was still a teenager, but took a sabbatical to earn a religious studies degree from the University of Stirling and gained an officer's commission at Sandhurst. He rose to the rank of Major in the Royal Army Educational Corps, and made waves when he started an Armed Forces Journal magazine, where service personnel could voice concerns about military life. A series of articles and interviews in which he accused the Army of private-school bias upset the top brass, and he left in 1999.
After working for the Commission for Racial Equality Scotland, he was elected to Parliament as Labour MP for Falkirk West in a by-election in December 2000, increasing his majority at the following two elections and retaining the seat in 2010.