The shadow of “Westminster sleaze” again looms over the Houses of Parliament following the emergence of a fresh spate of lurid allegations about the behaviour of Britain’s elected representatives.An unnamed Conservative MP is reportedly facing suspension from his party after being accused of watching a pornographic video on his smartphone in the Commons in full view of colleagues.Meanwhile, a female Labour MP has claimed she was the made the subject of “vulgar sexual comments” by a member of her own party, casting further light on the casual sexism women in politics face every day following the furore caused by a Mail on Sunday story published over the weekend, in which another unnamed Tory MP made accusations of a sexual nature against Labour deputy leader Angela Rayner.The Sunday Times reported on the same day that 56 MPs, including three Cabinet ministers and two Shadow Cabinet members, were under investigation over claims of sexual misconduct and had been referred to Parliament’s Independent Complaints and Grievance Scheme.Of course, this is hardly the first time in living memory that the conduct of Britain’s political leaders has been found wanting – here is an overview of some of the biggest scandals of the last 30 years.A surprising affairThe publication of Conservative MP Edwina Currie’s diaries in 2002 offered the eyebrow-raising revelation that she had had an affair with future Conservative prime minister Sir John Major between 1984 and 1988 when she was a backbencher and he the party’s whip and both were married.David Mellor, aggrieved having himself been forced to resign from Mr Major’s Cabinet in September 1992 over an extramarital affair of his own, observed wryly that history might have been very different if his former boss’s infidelity had become public knowledge while he was still in office.Cash-for-questionsThe phrase “Westminster sleaze” first gained national prominence as a result of the “cash-for-questions” affair in 1994, when Conservative MPs Neil Hamilton and Tim Smith were forced to resign from government jobs after then-Harrods owner Mohamed al-Fayed revealed he had given them money in brown paper envelopes to ask specific questions in the Commons.The scandal also led to the jailing of former defence minister Jonathan Aitken over secret meetings with Saudi representatives and prompted the creation of Lord Nolan’s “seven principles of public life”, which all public officials are now expected to adhere to – selflessness, integrity, objectivity, accountability, openness, honesty and leadership.‘A moment of madness’Welsh Labour leader Ron Davies, Tony Blair’s secretary of state for Wales, resigned in late October 1998 after he was mugged at knifepoint by a stranger he had met on Clapham Common, south London, having agreed to go for a meal with the man, losing his wallet, mobile phone and keys in the incident in an area then-notorious as a pickup spot.Mr Davies was married at the time but divorced the year after his fall from grace.“It was a moment of madness for which I have subsequently paid a very, very heavy price and I am deeply sorry,” he famously said. “I bitterly regret it.”New Labour resignationsMr Blair served as PM from 1997 to 2007 and was forced to sign off on the resignation of a number of Cabinet ministers for a variety of transgressions, notably his transport secretary Stephen Byers, who reluctantly stepped down in late May 2002 after it emerged that one of his special advisers, Jo Moore, had sent an email on the day of the 9/11 terror attacks on New York City that advised: “It’s now a very good day to get out anything we want to bury.”Peter Mandelson was meanwhile forced to step down twice, first over an undeclared home loan from a fellow minister and, secondly, for allegedly trying to help a donor to the Millennium Dome with a passport application. More