Police are searching for a suspected sex attacker after a 13-year-old girl was raped on the bank of the River Thames near Kingston-upon-Thames in southwest London.

I would appeal to the couple who approached the victim to call us. They may hold vital information - Det Ch Insp Pete Condron, Met Police

The child was attacked in a grassy area near Barge Walk at around 10.45pm on Sunday 17 May. The day before she had allegedly met the man in Camden, north London and arranged to meet.

Police are seeking an Asian man thought to be in his late teens to early twenties wearing blue jeans and a dark coloured leather jacket in connection with the rape.

Det Ch Insp Pete Condron from the Metropolitan Police said police are also keen to trace a young couple who may have vital information about the rape. Both were thought to be in their twenties.

The woman, aged about 25, had fair skin, a blonde bob and denim jacket. The couple asked after the girl's welfare just after the attack and then walked on towards Hampton Court.

Det Ch Insp Condron said the young couple "may hold vital information about what happened."

The girl, who did not require hospital treatment following the rape, was taken to a Haven sexual assault referral centre.

DC Pete Condron of the Sexual Offences, Exploitation and Child Abuse Command, said:

"I would appeal to anyone who saw anything suspicious or has information to contact us immediately.

"In particular, I would appeal to the couple who approached the victim to call us. They may hold vital information about what happened."

Barge Walk runs between Kingston Bridge and Hampton Court Palace on the bank of the Thames. Patrols in the area have been stepped up following the attack.

Anyone with information about the rape is being asked to call the police incident room on 020 8721 4251 or via 101. To remain anonymous call Crimestoppers on 0800 555 111.