A SEX attacker has been told he will stay in jail until he does not pose a risk to the public.

Stephen Duckworth, 47, of Arran Avenue, Shadsworth, Blackburn, sexually abused a teenage girl over a period of time, Preston Crown Court was told.

A judge said he had no doubt the impact on the victim was substantial and long lasting.

The court heard he had been suffering from post-traumatic stress disorder at the time, having seen a friend die in front of him.

At an earlier stage of the proceedings, while Duckworth was on remand awaiting sentence, the court was told he had not eaten for weeks.

Duckworth had pleaded guilty to two offences of indecent assault and two of sexual activity with a child.

He was told he would have to spend a minimum of 18 months in prison, before he could be considered for possible release.

But Judge Philip Sycamore stressed "Only when the parole board is satisfied you no longer need to be kept in custody for the protection of the public, will it be able to direct your release. Until it is satisfied, you will remain in custody "You pose a very high risk of harm, both physically and psychologically, to young females."

The court had been told that in a victim statement, the teenager said she felt her life had become a complete nightmare.

At the sentencing hearing, defence barrister Judith McCullough said Duckworth had pleaded guilty to very serious offences and knew he would go to custody for a long time.

He had suffered from post-traumatic stress disorder the result of a friend dying in front of him, she said.

After that, the depression seemed to have played a large role in his life, Miss McCullough told the court.

He had no previous convictions for sexual offences and had been on remand in custody for nearly a year.

Miss McCullough said: "The defendant is deeply ashamed. At the time it began, he suffered from post traumatic stress disorder that may have had some bearing on his judgment.

"He has spent the whole of his time in custody on the medical wing. He says he has had a difficult time of it.

"If any lessons needed to be learned they certainly have. He is extremely depressed and does seem to have little hope."

Duckworth was banned indefinitely from working with children. He will be on the sex offenders' list indefinitely and subject to a sex offenders' prevention order.