The MP arrested after a fracas in Parliament on Thursday has denied being drunk at the time of the incident, and denied being an alcoholic.
Eric Joyce, the independent member for Falkirk, was also arrested in February last year for attacking and head-butting Tory MPs in the House of Commons' Strangers bar. At the time he represented Labour, but the party withdrew the whip over the incident.
He was fined £3,000, and insisted he would continue as the MP for Falkirk until the next election in 2015.
The second incident, which reportedly started at a parliamentary karaoke night, has increased the pressure on his position.
Today, in a post on his personal website, he tried to set the record straight over this week's arrest.
He wrote: "I am not, and never have been, an alcoholic. I did, briefly, go through an unhappy period where I drank heavily. That ended 12 months ago, overnight, with the dreadful incident in Strangers for which I still feel genuine remorse in respect of those affected."
"I was not drunk last Thursday. I had consumed, by any standards, a very modest amount of alcohol. I was examined by a nurse after being arrested."
Mr Joyce, a former Army Major, said he would not comment further while police were investigating, but added: "I separated from my wife seven years ago. We are on excellent terms. I am not broken, tortured, lonely or tormented.
"It is widely known that I am very fit and healthy. I conduct my work as an MP with diligence, particularly on behalf of constituents and also matters relating to Africa and wider international development issues."
Scotland Yard said a man in his 50s was arrested after reports of a disturbance at a Commons bar just before 10.30pm on Thursday.
On Friday John Bercow, the Commons Speaker, announced Mr Joyce would be banned indefinitely from buying alcohol in the 27 places – including eight bars – where it is served at Westminster.