Sex crimes link to Tinder, Grindr
Crimes linked to dating apps Tinder and Grindr, including rape, child-sex grooming and attempted murder, have increased seven-fold in only two years.
More than 400 offences with a connection to users of the apps were reported to police last year and campaigners warned that many more were unreported.
They said the apps' users were vulnerable to extortion and urged better awareness of the dangers of meeting strangers online.
Offenders have been jailed for trying to blackmail users of Grindr, which is a gay dating app, and a man was suspected of raping a woman he met through Tinder.
Andy Cooke, who heads the UK police's violence and public protection division, said: "The rising popularity of online dating apps and websites has contributed to an increase in the number of recorded crimes.
"Those who use online dating apps should be security conscious and not share personal data with anyone until they are sure about who they are."
Police in England and Wales received 55 reports of crimes in 2013 in which Grindr or Tinder were mentioned.
This increased to 204 in 2014 and 412 in the year to October 2015, according to the 30 UK police forces that provided the figures.
Reports of violence and sexual crimes were the most common, with 253 allegations of "violence against the person" and 152 reports of sex offences: grooming, rape and the sexual exploitation of children.
Gay and human rights campaigner Peter Tatchell said: "I suspect these figures are just the tip of the iceberg."
Andy Phippen, professor of social responsibility in information technology at Plymouth University, said: "If we are going to base the formation of a relationship on a photo and a few lines of text, how do we know that person is who he says he is and has the right intentions?
"It is something we tell kids about - don't trust people online - but the adult population go merrily about their way thinking it is a good way of hooking up."