French prosecutors have opened an investigation into a Nazi-themed party attended by Conservative MP Aidan Burley, it was announced today.
A spokesman for the public prosecutor in the Alpine resort of Albertville confirmed that a preliminary inquiry has been launched, but refused to comment further.
The news prompted calls from Labour for Prime Minister David Cameron to withdraw the whip from the Cannock Chase MP until the inquiry is concluded.
Mr Burley, who has apologised for the incident, has already been sacked from his unpaid Government job as a parliamentary private secretary over the affair.
But Labour MP Ian Austin today said the PM should go further: "David Cameron and the Tories tried to brush this under the carpet, but the scandal surrounding Aidan Burley's disgraceful conduct is not going away.
"Surely the Prime Minister must take the whip off Mr Burley while this investigation is taking place."
It is understood that the investigation was prompted by a complaint from French pressure group SOS Racisme over the stag party in a restaurant in the ski resort of Val Thorens.
Reports suggest that one of the 12 friends attending wore a replica SS officer's uniform, while another toasted the Third Reich and there were chants of "Himmler, Himmler, Himmler".
Under French law, it is a crime to wear uniforms, insignia or emblems linked to the Nazi regime, unless they are being used for a film, play or historical exhibition.
Mr Burley today told the BBC: "They are launching a preliminary investigation and I understand I am not the focus of it.
"I do not believe I have broken any French law and have distanced myself from the behaviour of other people on the stag."
In a message to constituents yesterday, the MP voiced his "deepest regret", adding: "There are no excuses for my foolish behaviour which, over the past two weeks, has caused so much distress to so many people.
"I made a bad error of judgment and you deserved better from your local MP.
"Being involved in a stag party where an SS uniform was worn was wrong and offensive. It was the wrong decision on my part; crass and insensitive.
"I am deeply sorry, and want to take this opportunity to offer the people of Cannock Chase an unreserved, wholehearted and full apology for the terrible offence this incident has undoubtedly caused."
Mr Burley said his family had "been through hell" as a result of the publicity surrounding the party.
And he insisted: "I have no sympathies whatsoever with Nazism, racism, or fascism... I personally did not participate in any alcohol-fuelled attempted toasts by other guests to the Third Reich.
"Nor did I participate in any chants, offensive or otherwise. As the video showed, I left the restaurant immediately when that inexcusable behaviour by other guests started."