More than a million British adults have subscribed to extramarital affair dating websites, with up to 400,000 unique users logging on each week.
The sites have experienced a steep rise in demand, with some regularly seeing more female users than male.
Members are able to access the profiles of other would-be adulterers in their area and make contact through private messages.
Singles are also allowed to subscribe although the majority of users are married and middle aged.
MaritalAffair.co.uk, one of the largest sites of its kind, has almost 600,000 members. Analysis shows most members are parents aged 35 to 54, university educated, and browse from their own homes. Women using the site on a weekly basis outnumber men three to one.
Ashley Madison, a US-based website specialising in “discreet affairs” said it received a new British member every 45 seconds. More than 150,000 Britons use the site each week.
Noel Biderman, the firm’s chief executive, told The Times: “The number of 50-plus married women in the UK joining us has surprised me. The foundation of our business in Britain is the married woman.”
He added: “I have been to London and a few other British cities where there are massage parlours and clubs with a wink towards gentlemen, but almost nothing for women.”
The company said it acquired more than 10,000 new users the day after Valentine’s Day, and most of them were married women. There were similar increases after New Year’s Day and Mother’s Day last year.
A survey by the site found revealed the capital of online adultery to be Manchester, where there is one subscriber for every 27 people.
Julian Brazier, MP for Canterbury and patron of the Conservative Christian Fellowship, said that extramarital dating sites were pushing Britain towards a “social breakdown”.
© Copyright of Telegraph Media Group Limited 2012