A group of children who helped snare a sex offender after he tried to show them disgusting photos on his phone have been praised by police.

Barry Powell, 54, of Tufton Street, Maidstone, approached two 12-year-old girls who were standing at a bus stop in Tonbridge High Street on July 19, and showed them an indecent image of a child asking if they liked it.

One of the girls shouted at him and as Powell walked away, followed him, telling her friends to call the police.

A 13-year-old boy who had seen the incident joined the girl and phoned the police, giving a commentary on what had happened and Powell's movements.

They alerted members of the public to his indecent conduct and, as he walked away, Powell swore at the children and told the passers-by that the girl was his daughter. He then threw his phone in the river to destroy any evidence.

Once Powell reached the railway station the girl told him to look at the CCTV camera and spoke to security staff. They, together with two off duty police officers, intervened and ensured Powell remained at the station until officers arrived and arrested him.

The girl then took officers back to the river and showed them where Powell had thrown his phone.

"I would like to commend the children who helped the investigation and in particular the two who followed Powell and ensured he was brought to justice" - Investigator Jane Gibson

He later admitted showing the images to the girls for sexual gratification. He said he had not expected the challenging response from the 12-year-old girl.

It later transpired Powell had approached two 11-year-old girls near Tonbridge Castle the same day and showed them an indecent image.

Powell was charged and in August, pleaded guilty to making indecent images of children, causing a child to watch a sexual act, and three breaches of a sexual offences prevention order issued in October 2011.

Maidstone Crown Court heard at the time of the most recent offences, he was on bail having been arrested on June 6 on suspicion of downloading indecent images of children.

Yesterday, he returned to the same court, where he was jailed for three years and eight months.

He will also be the subject of an extended three year licence on release and a 10-year sexual harm prevention order, and be placed on the sex offenders register indefinitely.

Investigator Jane Gibson of Kent Police’s Public Protection Unit said: "Powell’s actions are entirely unacceptable and have caused considerable distress to a number of children.

“He has also shown a blatant disregard for the criminal justice system by committing offences while on bail and being subject to a sexual offences prevention order.

“I would like to commend the children who helped the investigation and in particular the two who followed Powell and ensured he was brought to justice.

“They were praised highly by the judge when Powell was sentenced and were recently presented with a certificate of merit by Kent Police.

“They should be very proud that their brave actions have protected other children from Powell’s offending.”