Police have admitted they may have to work with “paedophile hunters” after research revealed a rise in their evidence being used in court.
Figures obtained by the BBC show 11% of court cases in 2014 for the crime of meeting a child following sexual grooming used vigilante evidence, rising to 44% in 2016.
The vigilantes pose online as children then film the people they meet.
Police have urged them to stop, but admitted this was proving difficult.
‘Paedophile hunter’ evidence used in court cases
2014: 20 out of 176 cases
2015: 77 out of 256 cases
2016: 114 out of 259 cases
Source: BBC Freedom of Information request from 44 police forces in England, Wales and Northern Ireland
Chief Constable Simon Bailey, the national lead for child protection at the National Police Chiefs’ Council, said: “[These] vigilante groups are putting the lives of children at risk.
“They might not perceive it that way, but they are potentially compromising our operations.”
However, Mr Bailey said: “I’m not going to condone these groups and I would encourage them all to stop, but I recognise that I am not winning that conversation.”
When asked whether police could work with vigilantes, he said: “I think that’s something we’re going to have to potentially have to look at, yes, but it comes with some real complexity.”
Last week 45-year-old David Taylor from Trowbridge, Wiltshire, was jailed for 40 months after being caught by an unnamed vigilante who posed as an 11-year-old girl.
Police traced Taylor from a video of the confrontation posted on Facebook.
Southampton-based paedophile hunter Stephen Dure, known as Stevie Trap, has seen his evidence, including chat logs of his online conversations with suspects, used in three court cases this year.
In one case he posed as a 14-year-old boy when chatting to Robert Babey who is due to be sentenced later this month after admitting multiple breaches of his Sexual Harm Prevention Order.
Mr Dure said: “I’ve had policemen come up to me to shake my hand… to thank me. Whereas high-up police are trying to stop us.”
He said one issue raised by officers had been him posting videos of his stings online before cases had come to court.
“If that’s the way they want to go then fine I won’t upload the videos.”
Reacting to Mr Bailey’s statement that the police would think about working with vigilantes, Mr Dure added: “I think it’s great and just the idea they’re thinking about it excites me.
“I really look forward to it and hope it happens in the future, I would be very willing to work with the police.”
You can see more on this story on Inside Out on BBC One in the South at 19:30 BST on Monday. The programme will also be available on the BBC iPlayer after broadcast.