Mr Evans, a Deputy Speaker of the House of Commons, is tonight being questioned over claims made by the two alleged victims.
They claim to have been raped and sexually assaulted between July 2009 and March 2013 at his constituency. Both were in their twenties at the times of the attacks, although their exact ages have not been disclosed.
The Conservative MP was arrested at his home in Pendleton, Lancashire, this morning and is understood to be still in custody for questioning. The property has been searched by officers.
David Cameron, the Prime Minister, was informed of the arrest today, as was John Bercow, the Speaker of the House of Commons.
Mr Evans, 55, is openly gay, having disclosed his sexuality in 2010. At the time the MP for Ribble Valley said he was “tired of living a lie”.
A spokeswoman for Lancashire Constabulary refused to confirm if Mr Evans had been arrested. It was separately confirmed by Downing Street sources.
The spokeswoman said: “A 55-year-old man from Pendleton in Lancashire has today, Saturday, 4 May 2013, been arrested by Lancashire Constabulary on suspicion of rape and sexual assault.
“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.”
Mr Evans, a former Tory Party vice-chairman, came out as gay at the launch of a Parliamentary group set up to help MPs and staff be open about their sexuality.
He had received threats of blackmail in the past over his sexuality, he said.
He said of a former Labour MP: “The MP was saying to anyone who would listen, 'Why is it that Nigel Evans leads a life whereby he is gay to some people and not others?’ “
He added: “I could not afford it to be used as leverage against me. I couldn’t take the risk. I don’t want any other MP to face that kind of nastiness again.
“I am sure there are other gay MPs who would like to be open about their sexuality but are fearful of the consequences. I hope this new group will help them to do so.”
Mr Evans has been MP for Ribble Valley since 1992 and was elected as deputy speaker of the Commons in June 2010. In 1999 he was appointed as vice chairman of the Conservative Party, a post he held until 2001.
He is originally from Swansea and before becoming an MP he had a career working in his family’s newsagent business.
The naming of people who have been arrested is currently at the centre of controversy, with warnings that “secret arrests” are undermining the principle of open justice. Lancashire Constabulary said it had a long-standing policy of not naming people it had arrested. “We do name on charge,” a spokeswoman said.
When he came out as gay in 2010, Mr Evans admitted he regretted supporting Section 28, the law introduced by the Thatcher government banning local authorities from promoting homosexuality.
He said: "I was confused about how to protect youngsters at school. The law did the opposite of what was intended. We shouldn’t have been telling young people that being gay was wrong."
Asked in a newspaper interview why it had taken him so long to publicly disclose his sexuality, he said: "Growing up in the Sixties, it just wasn’t done. There were just as many gay politicians as there are now but none of them was out. I realised I was gay when I was about 12 or 13, though at the time I wished I wasn’t.
"I thought I might just be going through a phase and that it would fade away. I had a girlfriend.
"I suppressed it. In those days you kept it quiet. It was more or less impossible to enter politics – in either party – as an openly gay person. When Margaret Thatcher was asked about homosexuals in the party she said, 'Oh, we don’t talk about those sort of things.' It was all swept under the carpet.
"But it has all changed. First we had people coming out as gay MPs, and now openly gay people are being elected to Parliament. It is so much better."
The MP said his late father Albert would have found it hard to understand his sexuality.

 KalashnikovMarine wrote:
What is Operation Yewtree?

 Goliath wrote:
ITT: Guilty until proven innocent.

 dæl wrote:

 Goliath wrote:
ITT: Guilty until proven innocent.

And people wonder why there are calls for anonymity for the accused until prosecution.

 Goliath wrote:

 dæl wrote:

 Goliath wrote:
ITT: Guilty until proven innocent.

And people wonder why there are calls for anonymity for the accused until prosecution.

Exactly.
For the record, I'm not sure whether I think he did it or not.
The fact he was arrested did originally away me towards guilty, but upon finding that he was arrested due to claims by two friends of his, relating to four years ago, one of whom he was socialising with as late as last week, made me think there might be ulterior reasoning behind the allegations.

 Goliath wrote:
ITT: Guilty until proven innocent.

Steve steveson wrote:
The worst bit about the Operation Yewtree is that all of them are being treated as "Dirty dirty kiddy fiddlers".

 Albatross wrote:

Steve steveson wrote:
The worst bit about the Operation Yewtree is that all of them are being treated as "Dirty dirty kiddy fiddlers".

Hmm. I'd say the worst part about Operation Yewtree is all the abuse that went on, like....