Disgraced MP Eric Joyce has spoken of the night when he went "on the rampage" in a Commons bar, describing fighting as his "hobby".
Joyce, who resigned from the Labour Party after being convicted of four counts of assault in February, said he hit fellow politicians who tried to restrain him because they "presented targets".
He also boasted about his brawling technique, giving tips on how to inflict maximum damage when headbutting people.
The extraordinary comments came in an interview with the Mail on Sunday.
The former Army major and judo expert, who is standing down from his Falkirk seat at the next general election, said the spat in Strangers' Bar started when a friend of his began singing music from the Barber Of Seville.
Tory MPs and aides in the bar apparently objected, and Joyce said he pulled Tory Stuart Andrew's tie.
"The next thing I knew, the guy grabbed me,' Joyce said. "They were trying to hold my arms. Nobody had been biffed at this point. That was the flashpoint.
"There were lots of faces - they were just presenting targets, so once I had started I finished. They kept their heads close to me, which is never a good idea. They were trying - ineffectively - to restrain me, which is not a good idea either."
Joyce went on: "More seasoned folk in a bar would have just stepped away. I regard a tie tug as a fairly "stop p****** me off" kind of thing, not the equivalent of a punch in the mouth. They probably thought, 'This bloke is going mental'.
"At that point, I saw red. I thumped them with my fist and my head - not with massive viciousness, just enough to sting them."