Nigel Griffiths, the Labour MP for Edinburgh South, is facing the prospect of a parliamentary inquiry over a newspaper story that he had a sexual assignation with a woman in his Commons office on Remembrance Day.

Nigel Griffiths, the Labour MP for Edinburgh South, is facing the prospect of a parliamentary inquiry over a newspaper story that he had a sexual assignation with a woman in his Commons office on Remembrance Day.

The office of Parliamentary Standards Commissioner, John Lyon, yesterday confirmed he had received e-mails of complaint over the former minister's conduct.

Mr Griffiths, a former deputy leader of the Commons and a close friend of Prime Minister Gordon Brown, at first angrily denied the allegations of a late night tryst in his Commons Office, but then issued a contrite apology when a Sunday newspaper published photographic evidence of the encounter.

He has since acknowledged his behaviour fell below "acceptable standards"

A spokeswoman for Mr Lyon said: "He has received complaints by e-mail, and we are looking at them." The Commissioner, who reports to the Standards and Privileges Committee, may consider the complaints, including from whom they originate, before deciding to launch an inquiry or dismiss the matter.

Mr Griffiths, who has been married to wife Sally for 30 years, said he had little recollection of the evening in question but that did not excuse his behaviour. "I am, of course, ashamed that my conduct did fall below acceptable standards," he said.

Mr Griffiths was back at work in the Commons yesterday, attending the Public Accounts Committee he is a member of, but refusing to comment further on the incident or the complaints against him.

With the photographic documentation lending strength to the feeling in Westminster that there was an element of collusion or even entrapment in the story most MPs expressed their private sympathy for Mr Griffiths and his wife.

"I have known Nigel for many years, as a friend and as a hard-working constituency MP," said Jim Devine, Labour MP for Livingston. "This is a difficult time for him and his family, but it is an entirely personal matter for him to deal with."

The Edinburgh South's Labour colleagues closed ranks in support of him last night. "There is about as much legitimate public interest here as there was with the tabloids claiming David Mellor was too exhausted to do his job as a minister because he had spent the night with actress Antonia de Sancha," said a Scottish Labour MP.

Even Mr Griffiths' political opponents came to his support. Neil Hudson, the Conservative candidate for Edinburgh South, said it was "a shame the MP for Edinburgh South has become embroiled in this rather sad story".

Mr Griffiths is defending a majority of just 405 votes in the seat he has represented, with boundary changes, since 1987. Fiercely loyal to Gordon Brown, he has held a number of other Government positions, including Construction Minister and Enterprise Minister.

Mr Griffiths, who was previously deputy leader of the House of Commons, resigned from Government in March 2007 over his opposition to funding new Trident nuclear submarines.

A spokesman for the Prime Minister said that as Mr Griffiths was not a member of the Government the matter was a personal one for him to deal with. A similar line came from the Scottish Labour Party. "We expect all MPs to engage with the parliamentary authorities and have no doubt that will happen," said a spokesman.