Eric Joyce, the Labour MP for Falkirk in Scotland, has been suspended and charged by police following allegations he head-butted openly gay MP Stuart Andrew in a House of Commons bar, months after Andrew spoke to the House about being the victim of assault.

A Labour Party spokesperson confirmed: “This is an extremely serious incident. We have suspended Eric Joyce pending the results of the police investigation.”

The incident is alleged to have taken place at 11pm on Wednesday evening.

There is no indication it was motivated by homophobia.

Scotland Yard 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.”

Andrew was thanking constituents and other well-wishers for their support on Twitter late last night. Joyce was being held in police custody.

The incident comes months after the MP for Pudsey spoke openly in the Commons about being the victim of a homophobic assault.

In November 2011, he said: “One in five gay and lesbian people has experienced a homophobic attack in the last three years.

“As someone who experienced such an attack in the 1990s, I am aware of the fear that goes on after such an attack.”

The incident at the Palace of Westminster’s Strangers Bar was reported to have also involved a Labour whip and Alec Shelbrooke, MP for Elmet and Rothwell, who was said to have been left with a bloodied shirt.

The parliamentary watering hole has been described by gay Labour MP Chris Bryant as “virtually a gay bar” on some evenings.

Speaking at a debate on Parliamentary representation in January, Bryant said: “It is significant that we now have more out gay Members of Parliament than ever before.

“Indeed, sometimes when you go into the Strangers Bar you feel as though you are in Rupert street. It is virtually a gay bar now, and my husband sometimes worries about whether I should be allowed in there any more.”

Speaking in the Commons about the incident yesterday, 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. I would ask that no further reference should be made to these reports in the Chamber today.”