Story highlights Nigel Evans resigns as deputy speaker of the House of Commons after charges

He says he'll remain in Parliament to represent his constituents

He faces a total of eight counts, including one rape charge, and insists on his innocence

He's a member of the ruling Conservative Party, which declined comment

The deputy speaker of Britain's House of Commons resigned Tuesday after being charged with a variety of sexual offenses, including rape, in cases dating more than a decade.

Nigel Evans, a member of the ruling Conservative Party, said he would "robustly defend my innocence" when the case goes to trial. But he said he would remain in Parliament, just not in the leadership, to continue to represent his constituents.

"Whilst I am saddened that this case has not been closed today, I am certain of two things: firstly that I am innocent, and secondly that my innocence will be demonstrated," Evans said in a statement.

Evans has been charged with one count of rape, five counts of sexual assault -- a charge involving allegations of intentional, unwanted sexual touching -- and two counts of indecent assault. The eight counts involve a total of seven people, prosecutors said.

All of the victims in the charges are men, prosecutors said in a statement announcing the charges. Evans came out as gay in 2010 and has made a name for himself as a prominent gay rights activist in England.

The investigation began in May, when Evans was arrested and questioned by police after two men in their 20s leveled accusations against him. The charges date back as far as 2002, prosecutors said.

Evans has been a member of Parliament since 1992 and served as the Tories' vice chairman between 1999 and 2001. The Conservatives had no comment on the charges, calling it a police matter.