Police chiefs have accused vigilante paedophile hunters of exceeding the law, despite using their evidence to prosecute suspects in more than half of all cases.
Senior officers have criticised the online groups – who pose as youngsters in order to smoke out predatory paedophiles – claiming some are guilty of offences such as blackmail, extortion and violence.
But despite these reservations the most recent figures reveal the extent to which police forces rely on evidence gathered by such gangs to catch offenders.
According to data obtained by the BBC under the Freedom of Information Act, 403 people were prosecuted in 2018 for the offence of attempting to meet a child following sexual grooming.
More than 250 of those were charged following evidence gathered by paedophile hunting groups and in some force areas it accounted for 100 per cent of all cases.
An analysis of crime statistics shows how convictions for grooming offences have rocketed more than five fold since 2013, suggesting the emergence of paedophile hunter groups is helping to bring more dangerous predators to justice.
In 2013 there were just 68 people convicted of grooming offences, but by 2018 that figure had risen to 359.
But despite this, Assistant Chief Constable Dan Vajzovic, the National Police Chiefs’ Council lead on online child abuse groups, expressed major concerns around the way the groups operated.
He suggested some were even committing offences themselves, including extortion, blackmail and violence against those they were targeting.
Mr Vajzovic also suggested some of the prosecutions were diverting police resources away from more serious offenders.
He said: “When these groups say they are acting in the interests of children, largely they are acting in their own interests, their self-aggrandisement and their desire to exercise force against so called perpetrators of child abuse.
“They don’t put measures to safeguard children they don’t put in measures to identify other offenders who may be connected to the people they are targeting. They are more interested in putting a video online of them carrying out a sting.”
Last year a judge criticised vigilante groups warning that they were becoming a “cottage industry” after it emerged that one suspect had been targeted by three separate groups at the same time.
A spokesman for the NSPCC also expressed concern that sometimes the groups were forcing suspects underground, rather than bringing them out into the open.
The spokesman said: “We have sympathy for those who worry about suspected abusers, want justice for children and feel frustrated that police can’t do everything.
“However, despite their best intentions, their actions might put more children at risk of harm by driving offenders underground, endangering ongoing police work and the legal process, or result in innocent people being targeted.”
Jim Gamble, who used to run the Child Exploitation and Online Protection Command (CEOP) recently warned that paedophile hunter groups tended to attract people who were trying to mask their own problems such as domestic violence records.
Mr Gamble has called for a law to ban people posing as a child online without a reasonable excuse or lawful authority and instead has called for a ‘citizens’ army’ of more than 1,000 volunteer special police constables, trained to catch paedophiles online.