Millions of sex-seekers could have their details made public after a "sex and swingers" website suffered a major hack.
Intimate information of around 400 million accounts linked to Adult Friend Finder, including those of five million Britons, may be at risk, according to a report by monitoring group Leaked Source.
The group said the breach was "the largest we've ever seen" and it dwarfs a similar attack on marital affair site Ashley Madison last year.
Information including emails, passwords and purchasing habits over a 20-year period is said to have been hoovered up - even from deleted accounts.
The site promises to "satiate your need for amazing sexual experiences" and boasts it has helped "millions of people" find swinger groups and threesomes.
Parent company Friend Finder Networks also owns adult webcam sites which are said to have been affected too.
Vice president Diana Ballou told technology site ZDNet: "Over the past several weeks, Friend Finder has received a number of reports regarding potential security vulnerabilities from a variety of sources.
"Immediately upon learning this information, we took several steps to review the situation and bring in the right external partners to support our investigation.
"Friend Finder takes the security of its customer information seriously and will provide further updates as our investigation continues."
Leaked Source said it would not make the information searchable "for the time being" after "much internal deliberation".