The NSPCC has welcomed the conviction of two South Hams men who were trapped by internet paedophile hunters but warned that vigilante groups risk driving offenders underground.

The child welfare charity said the job of tracking down online sex offenders should be left to the police rather than private individuals.

The charity spoke out after two men were sentenced in one day at Exeter Crown Court after being trapped by paedophile hunters who posed as under age girls in chat rooms and dating sites.

Former Royal Navy steward Michael Watton, 56, of Church Road, Dartmouth, was jailed for 16 months after he admitted trying to contact 10 girls, including one aged just 10.

He was trapped by groups called Dark Justice and Internet Interceptors after going to Paignton station to meet a fictitious 14-year-old girl called Ellie May.

Carer David Hack, 34, of Churchstow, near Kingsbridge, was jailed for 16 months, suspended for two years, and sent on a sex offenders course.

He was detained by members of the Plymouth Against Paedophiles group after going to meet a 15-year-old decoy named Felicity at a supermarket.

Commenting on David Hack’s case, an NSPCC spokesman for south west England said the sting operation had exposed him as a danger to children, but expressed doubts about vigilante activity.

The spokesman said:“Hack’s shocking behaviour highlights the dangers posed to youngsters by offenders online.

"He fully believed he was speaking to a 15-year-old girl, but continued to groom her for sex before attempting to meet her. This kind of predatory activity can ruin childhoods, with the devastating effects lasting into adulthood.

“While we have every sympathy for people concerned about suspected abusers, we believe that identifying offenders and investigating crimes is best left to the police.

"When members of the public take the law into their own hands it can run the risk of driving offenders underground, endanger on-going police work and the legal process or result in innocent people being targeted – all of which may put more children at risk of harm.

“If someone has concerns about a child’s safety the best way they can help is to alert the police. By speaking out they may be able to help investigations and contribute vital evidence.”

Any adult concerned about the welfare of a child or young person can also call the NSPCC helpline for free 24/7 on 0808 800 5000. Meanwhile, children can call Childline on 0800 1111.