Detectives in Chorley are appealing for information about an alleged serious sexual assault on a four-year-old girl which took place 11 years ago.

Police said the girl was playing on an un-adopted road opposite the town's Regent House Surgery, Regent Road, one Saturday afternoon in October 1997.

She was playing on her bicycle when she fell off and was then approached by a man who was parked in a 'scruffy' white van.

He is alleged to have taken her to his van, saying he was going to put a plaster on her knee.

Once inside he is alleged to have sexually assaulted her and told her not to tell anyone.

She finally disclosed the incident in December 2007.

The man at the time was described as white, aged in his 50s, with white or grey hair.

He had a plumpish build and was very scruffy in appearance.

The van he was driving was possibly a white Bedford Rascal van or a similar small van, with possibly cardboard or similar was obscuring the back window.

Police are appealing for anybody with any information about this incident to contact them.

Detective Inspector Graham Coates, who is leading the investigation, said: "I appreciate that this incident happened more than ten years ago but there is a chance that someone out there is able to cast their mind back and recollect something that could help us with our investigation.

"I would like to speak to anybody who thinks they may know a man who matched that description and who drove a small white van at the time.

"If you think you may have known the man or come into contact with him at the time but haven't seen or spoken to him since we would still really like you to come forward."

Anybody with any information should contact Chorley CID 01257 246222.