Deputy House of Commons Speaker and Conservative MP Nigel Evans has been arrested on suspicion of rape and sexual assault, sources said.
A spokesman for Lancashire Police said that a 55-year-old was arrested in the village of Pendleton near Clitheroe on suspicion of rape and sexual assault.
The alleged victims are understood to be men in their 20s.
It is understood that Prime Minister David Cameron has been made aware of the arrest. A House of Commons spokesman would not comment, and said it was a police matter.
The police told the Sunday Mirror: “The man will be interviewed at a police station in Lancashire during the course of the day.
“The offences are alleged to have been committed in Pendleton between July 2009 and March 2013.
“We take all allegations of a sexual nature extremely seriously and understand how difficult it can be for victims to have the confidence to come forward.
“As a Constabulary, we are committed to investigating sexual offences sensitively but robustly recognising the impact that these types of crimes have on victims.
“We would encourage anyone who has experienced sexual abuse, or who has information about it, to have the confidence to report it to us knowing that we will take it seriously, deal with it sensitively and investigate it thoroughly.”
Conservative MP Evans, who is from Swansea, was promoted to Deputy Speaker in 2010. He came out as gay that same year, saying that he was "tired of living a lie".
He told the Mail on Sunday that he been threatened with exposure by political opponents.
He has previously been a vice chairman of the Conservative Party from 1999 to 2001.
Under Iain Duncan Smith's leadership of the party, he was promoted to the shadow cabinet as shadow Welsh secretary - a post he held for two years.
Pendleton residents told the Sunday Mirror they were stunned to learn of Evans' arrest.
One neighbour said: "It's shocking. I've known him for 12 years, ever since I moved here.
"He's always been such a nice neighbour. There have been lots of police cars coming and going, which is not something we ever see here.
"The thought of him being arrested for rape is truly shocking. He's always seemed so pleasant."
The newspaper added that blinds were lowered at Evans' home and that no one appeared to be at home.
Michael Ranson, the chairman of the Ribble Valley Conservative Association, said people in the constituency were "completely shell-shocked" at the news.
"He is a very popular MP and a very good constituency MP. He's given assistance to a lot of his constituents over many years," he told Sky News.
"Everybody's completely shell-shocked."