A leading light in student politics and member of an elite university drinking club, Benjamin Sullivan, the President of the Oxford Union, has been released on bail until 18 June after being arrested on suspicion of rape and attempted rape.

The arrest took place in Oxford this morning. It is understood that the 21-year-old undergraduate, studying at Oxford University’s Christ Church College, has not been charged with any offence.

Mr Sullivan, who heads the largest student society in the University of Oxford, has been dogged by controversy in recent weeks after his membership of a drinking society dubbed the ‘Banter Squadron’ was revealed. He initially denied the claims, reported by a student news website, The Tab Oxford.

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A bitter row ensued which resulted in Mr Sullivan attempting to get the Oxford Union to fund legal action against the website. But he backed down last week amid mounting criticism of his plans to use the debating society’s funds to fight his corner. And last Friday saw the Union’s librarian, Kostas Chryssanthopoulos, resign over the affair. In his resignation email, Mr Chryssanthopoulos stated: “To serve under this President has been the biggest regret of my time in this Society and I want nothing more to do with him.”

In an open letter posted on the website of Oxford student newspaper Cherwell on Tuesday, Mr Sullivan apologised for denying his links to drinking society. “I regret that decision and would like to apologise for it.” He “panicked” when faced with a “public attack in the press” and described the Banter Squadron as “a joke term used to describe our group of friends”.

The letter had been removed from the website yesterday, when reports of the arrest began to circulate. A spokesperson for Thames Valley Police said: “I can confirm a 21-year-old man from Oxford has been arrested today on suspicion of rape and attempted rape in Oxford; he is currently in custody.” They would not elaborate on details of the alleged offences.

And in a statement, The Very Revd Christopher Lewis, Dean of Christ Church, commented: “We have nothing to add to the police statement which is that a 21-year-old was arrested on suspicion of rape and attempted rape except to say that that person is a member of this college.”

Mr Sullivan is on a sabbatical year from his BA in History and Politics and had planned to work as a researcher for Lord Browne, former BP boss, when his term as Oxford Union president ends next month. The debating society has been a breeding ground for future Prime Ministers and politicians since it was founded in 1823, with William Gladstone, Herbert Asquith and Edward Heath among its alumni. In more recent years, it has been a stepping stone to success for the likes of Michael Gove, the education secretary, and Boris Johnson, the mayor of London.