Shamed politician Eric Joyce was arrested following a late-night brawl at a bar in the House of Commons on Thursday night.
The independent Member of Parliament for Falkirk was held after the incident at the Sports and Social Club bar.
Last year Joyce pleaded guilty to assault after an incident in Parliament's Strangers Bar. He resigned from the Labour Party and said he would not contest the next General Election.
On Thursday night a Metropolitan Police spokesman said: "Police were called shortly before 10.30pm this evening to reports of a disturbance at a bar within the House of Commons.
"Officers attended and a man aged in his 50s was arrested in connection with this incident.
"He remains in custody and inquiries continue."