The girl, also 17, was found with serious head injuries and stab wounds in Wood Green and is in a critical condition in a north London hospital.

It is believed the assault took place behind garages at the rear of Wendover House in Palmerston Road, near the A406 North Circular Road, on Monday.

The boy remains in custody at a north London police station.

Det Ch Insp John Macdonald said: "We are appealing for witnesses to come forward after this terrible attack."

"Given that this happened on a Bank Holiday and in daylight we hope that there will have been people in the area who may have seen somebody acting suspiciously or heard something that may be vital to our enquiry."