Image caption Mr Joyce has been an MP since 2000

Labour MP Eric Joyce has been suspended from the party after he was arrested over allegations of an assault in a House of Commons bar.

Police were called after reports of a disturbance on Wednesday night.

Mr Joyce, 51, remains MP for Falkirk but cannot take the Labour whip until the police investigation ends.

Speaker John Bercow has said he takes the matter "very seriously". The Conservative MP for Pudsey Stuart Andrew has alleged he was assaulted.

The BBC understands officers involved in the investigation returned to the Commons on Thursday evening to interview eyewitnesses.

BBC political correspondent Iain Watson said it had also been alleged that Mr Joyce - who is still in custody and has not been charged with any offences - was involved in an incident after being taken into police custody on Wednesday evening.

Labour MPs say they are concerned about Mr Joyce's health and behaviour, he added, and the party is not ruling out the possibility of a by-election in Falkirk.

The disturbance is believed to have happened in the Strangers Bar, which is reserved for MPs and their guests.

Mr Andrew was in the bar following a Commons event organised by his Conservative colleague Andrew Percy, for the Speaker of the Canadian Parliament.

'Extremely serious'

A Scotland Yard spokesman said: "We were called at approximately 10.50pm last night to reports of a disturbance at a bar within the House of Commons.

"A man aged in his 50s was arrested by officers on suspicion of assault. He remains in custody in a central London police station. Inquiries are continuing."

A Labour Party spokesman said: "This is an extremely serious incident. We have suspended Eric Joyce pending the results of the police investigation."

In the Commons, Speaker John Bercow said: "Members will be aware of reports of a serious incident in the House last night. 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."

Mr Joyce was elected in a by-election in December 2000 and has served as a parliamentary private secretary (PPS) to a number of government ministers since 2003.

He was PPS to the then defence secretary Bob Ainsworth until 2009, and prior to that had been a parliamentary aide to John Hutton, Mike O'Brien and Margaret Hodge.