It is found behind an old wooden door in a corner of the Houses of Parliament - an old-fashioned bar “up to train station standards” says political blogger Paul Staines.

Salient features: wooden-panelled walls, sticky green carpet, elbow-high tables to rest a taxpayer-subsidised pint of ale on, a door for smokers to head out to the terrace by the Thames…oh, and MPs who’d like to have sex with you.

In Labour’s heyday the bar’s nickname was the Kremlin. Now it’s been rechristened (by MP Chris Bryant) the Palace of Versailles.

Sleaze, it seems, is well and truly back – if it ever went away – at Britain’s centre of political power.

“There’s a climate of sexual harassment going on in Parliament that the parties have no interest in dealing with,” said young political journalist Alex Wickham.

He described the late-night scene at Strangers’ for Spectator magazine. “Standing in the middle of the room, hands clasped behind their backs and beer bellies sucked in, [MPs] survey the crowd,” he wrote. “If things have gone well at Strangers’, it is on to the downmarket Players piano bar in Charing Cross for the MPs and their new friends.

“It was there that one Tory, a headline name, decided to run his hand up my thigh as the pianist played songs from Cabaret.”

The last few days have heard many more claims of alcohol-fuelled sexual harassment by MPs against their younger staffers.

Political journalists have told tales, albeit not naming names, of a culture of affairs, late-night assignations and wandering hands between young and old, gay and straight, left-wing and right-wing – mostly, but by no means all, consensual.

“The historic Palace of Westminster is home to a subculture of booze-fuelled revelling that puts many a university campus to shame,” reported The Guardian. An unnamed researcher told the paper: “Double standards…not only apply to gay MPs masquerading as straight, but also to senior politicians who were publicly happily married but who had a predatory approach to young female staff.”

In The Times, political correspondent Laura Pitel quoted an unnamed “rotund young man” in a Soho bar explaining how he met a married MP on [hook-up app] Grindr – “then he gave me a job”.

Wrote Pitel, “It is a common sight to find middle-aged MPs, spin doctors and journalists mixing [at Strangers’] with the twenty-something political obsessives who work behind the scenes”.

“For some the culture in Westminster breeds fun, friendships and powerful allegiances. Others say there is a lack of boundaries that is open to exploitation by the MPs who have sole responsibility for hiring and firing their staff.”

Channel 4 News interviewed 70 researchers, activists and MPs from all political parties and found a third had experienced sexual harassment which they saw as an abuse of power - and a further 21 per cent said they had witnessed or heard of sexual harassment.

However, they described a “culture of silence”, with the young victims hopeful of a career in politics and fearful of blighting their reputation.

Gay equality campaigner Ben Summerskill said sexual harassment was “part of the culture of Westminster” and he had heard of dozens of cases.

“The MP can say that if they oblige them, it might help their career enormously,” he said. “People are vulnerable as they’re often political obsessives and have never worked anywhere else.”

The cue for this Westminster confessional has been the sad case of former Commons deputy speaker Nigel Evans.

Last week Mr Evans was cleared of nine charges of rape and sexual assault.

However, he admitted having consensual sex with a man 33 years his junior who had previously done work experience at Westminster.

Prosecutors thought their case was strong. One after the other, his accusers gave evidence in court about Mr Evans’ “drunken overfamiliarity”.

Yet almost every one played it down. “I do not believe [Mr Evans] has committed any offences,” one said. Mr Evans tried to kiss him in the Strangers' Bar when he was a 21-year-old student. He said “no”, was left feeling “embarrassed and bewildered” but not assaulted.

In reaction to the bad press, Conservative chief Whip Sir George Young drew up a new code of conduct on Friday, warning MPs to treat their staff with dignity and respect, and “not use their position to bully, abuse or harass employees”.

“The Tories have put down a marker,” says Staines. But he’s cynical as to how much difference it will make.

“It’s always been this way,” he says. “Some of these guys wouldn’t get laid if they weren’t MPs. And some [of the staffers] are completely up for it.”