A police officer was punched in the head and stabbed after chasing a thug through the streets of south-east London.

The teenage suspect was Tasered when backup arrived to detain him after a fight broke out in Perryvale Avenue in Forest Hill.

Officers were called to reports of two men involved in an altercation on the street at about 8pm on Friday.

Both suspects fled when police arrived, and when the male officer caught up with the 18-year-old the stabbed in the left arm and punched in the head.

When support officers arrived the teenage boy was arrested on suspicion of a weapon and grievous bodily harm. A Taser was deployed, the Met said.

The injured policeman was rushed to hospital but discharged hours later.

The suspect was taken to a south London police station, where he remains.

A Met Police spokesman said: “London Ambulance Service were called to the scene, and the officer was taken to hospital for treatment on a minor injury.

“He was discharged some hours later and is now recovering well at home.”