The political career of Conservative MP for the Ribble Valley may be at risk following the arrest on Saturday of 55-year-0ld Nigel Martin Evans on charges of rape and sexual assault filed by two men in their 20s.

Mr Evans, the deputy speaker of the House of Commons, who admitted to The Mail on Dec 18, 2010 that he is gay, denied the accusations. He was arrested at his house in Pendleton by the Lancashire Constabulary, but is out on bail until June 19.

Reports said the sexual assault happened between July 2009 and March 2013. The MP, until the case was filed, regarded the two men as friends with whom he continued to socialise with until as late as last week.

Mr Evans said he will not stand down as deputy speaker or MP, but Defence Secretary Philip Hammond said while he believes people accused of crimes should be treated as innocent until proven guilty, Mr Evans would find it very difficult to carry on with his duties as deputy speaker while the investigation is ongoing.

"It is quite difficult to carry out a sensitive and high-profile role while being under this kind of scrutiny," the Financial Times quoted the secretary.

Prior to his appointment as deputy speaker, Mr Evans served as vice chairman of the Conservative Party and was elected in 2010 as one of three deputy speakers.