A 13-year-old girl was sexually assaulted in Highbury this morning before a have-a-go hero stopped the attack.

Scotland Yard detectives are appealing for witnesses to the attempted rape at about 8.20am.

The girl was approached by a muscular white man who was about 6ft with black and grey hair. He put his hand over her mouth and forced her into Coach House Lane, Highbury.

A member of the public then witnessed what was happening and faced up to the man, allowing the girl to escape.

The man then stole a bike from a teenage boy and rode along Highbury Hill before dumping it and running off.

Police searched for the man but could not find him or the teenage boy. The attack was reported on behalf of the victim and is being investigated as an attempted rape.

Det Con Ben Lucas, of the Sexual Offences, Exploitation and Child Abuse Command, said: “Enquiries are underway to identify and arrest the suspect, who was bravely confronted by a member of the public, who no doubt prevented further serious offences from taking place.

“The victim is being supported by specially trained officers and is providing information to assist the investigation.

“We are very keen to hear from any witnesses to the incident itself and also anyone who saw the suspect making off along Highbury Hill.

“We would particularly like to speak to the boy whose bike was stolen by the suspect as he may have vital information that could help us to identify the suspect.

“I would like to reassure anyone who may be concerned about contacting the police that they will be treated with the utmost sensitivity.”

Police are asking anyone with information to call 101 or to remain anonymous, call Crimestoppers on 0800 555 111.