KARATE black-belt Brian Hanna, who sexually abused a teenager in Corsham during a hands-on martial art lesson, was jailed for four years today.

Brian Hanna, 47, lives with his mother in Plymouth at weekends and with his wife in Chippenham during the working week.

He was convicted of abusing a 15-year-old girl, who had a mental age of only seven, in a dark icehouse on a Corsham industrial estate where he worked as a full-time handyman.

Alan Fuller, prosecuting, previously told Gloucester Crown Court the girl was at a school sex education lesson discussing inappropriate behaviour when she let slip that Hanna had abused her.

Mr Fuller said: "She said this defendant touched her during karate lessons and took photos of her intimate areas.

"On another occasion he asked her to kiss him intimately. She said it was disgusting, like Pinocchio's nose."

She also described being taken to a cave, which was the icehouse on the industrial estate.

Defending his actions grey-haired Hanna told the jury that he had touched the girl but never with a sexual motive.

He said: "I have touched her breasts, but not in a sexual way."

He said he was teaching the girl the art of punching and blocking when it happened: "I threw a punch at her stomach and she wasn't quick enough to block it and my hand rested on her top, but only for a second."

Hanna maintained the girl had been following him around making advances but Judge Martin Picton convicted him of sexually touching the girl.

Marcus Davey, defending at the hearing, said: "There is no suggestion that these offences caused this girl any psychological harm.

"Custody will have a devastating effect on this man, who has never been to prison before and whose marriage is now effectively over."

Judge Martin Picton said: "It is frankly hard to imagine a more gross breach of trust than this.

"This girl had a mental age of seven and was a very vulnerable child.

"It seems to me obvious that what you did to her was very upsetting. This was a truly awful thing to do. It calls for and must merit a lengthy sentence."

Hanna was also ordered to sign the sex offenders register.