A Conservative MP who quit as a minister over an internet sex scandal is to stand down from Parliament, claiming the media spotlight had become "intolerable".

Brooks Newmark, who served as minister for civil society and founded the Women2Win campaign group, had exchanged suggestive pictures over the internet with a male reporter posing as a young Tory PR woman.

In a letter to the Prime Minister, the American-born MP for Braintree said he would quit at the General Election next May and appealed to the media to respect his family's privacy.

He asked that he be given a "chance to try to heal the hurt".

The 56-year-old married father-of-five sent pictures to a freelance reporter, who adopted the false identity of "Ms Wittams" and described himself on Twitter as a "twenty-something Tory PR girl".

"Sophie" then contacted and interacted with a number of Conservative MPs via the social networking site.

He wrote: "The continued media intrusion into past episodes in my personal life is placing an intolerable burden on my family. I have therefore decided to stand down at the General Election. I will continue to serve my constituents to the best of my abilities until that time.

"I again appeal to the media to respect my family's privacy and to give me a chance to try to heal the hurt I have caused them.

"I have no one to blame but myself.

"I will remain a loyal supporter of the Government and would like to thank the many friends and colleagues for the support and sympathy they have shown me and my family."

He tendered his ministerial resignation after learning that the newspaper was about to publish details of the online exchanges.