French prosecutors have launched a full inquiry into the Nazi-themed stag do attended by Staffordshire MP Aidan Burley.

According to French news agency AFP, the probe will look at allegations of defending war crimes or crimes against humanity; promoting racial hatred; wearing the uniform of an organisation that carried out crimes against humanity and making racist insults.

Albertville state prosecutor Patrick Quincy said no indivudual suspect had so far been targeted in the inquiry into the stag party, which took place on December 3 in a restaurant in the French Alpine resort of Val Thorens.

Mr Burley has repeatedly apologised for being present at the event, but said in December: “I do not believe I have broken any French law and have distanced myself from the behaviour of other people on the stag.”

The Tory MP for Cannock Chase has already lost his job as a parliamentary private secretary after reports of the party, at which one guest is alleged to have dressed in an SS uniform and others are said to have chanted Nazi slogans.

But there were calls for Prime Minister David Cameron to withdraw the whip, following the French announcement.

Black Country MP Ian Austin (Lab Dudley North) said: “Surely David Cameron has got to stop dithering and take the whip off Aidan Burley whilst the French investigation and Conservative Party investigation take place.

“The French authorities are clearly taking the disgraceful events at the stag party in which Mr Burley was involved very seriously and it is about time that David Cameron and the Conservative Party did the same”

A preliminary investigation was launched by French authorities December after a complaint from a French anti-racism group, and Mr Quincy told AFP that authorities were now moving forward with a full official investigation.

Mr Burley was photographed sitting next to the stag, who was wearing the black uniform of a World War II-era German SS officer.

A video showed a guest raising a toast to the Third Reich at the party and reports said the group had later chanted “Mein Fuehrer!” and the names of Nazis Heinrich Himmler and Adolf Eichmann.

In a statement after the incident, Burley voiced his “deepest regret” and insisted: “I have no sympathies whatsoever with Nazism, racism, or fascism.”

It emerged last December that Mr Burley had been relieved of his duties as aide to Transport Secretary Justine Greening after news of the stag event broke.

Mr Burley has been working to salvage his political career, including by writing a long letter of apology to the Jewish Chronicle and planning a visit to Auschwitz concentration camp in Poland.