A police officer is under criminal investigation after a man was tasered and left with 'life-changing' injuries.

Metropolitan Police on patrol in Harringay, chased a man in his 20s on Monday May 4 and tasered him as he jumped over a wall.

The Independent Office for Police Conduct (IOPC) said the man fell and suffered serious injuries, which meant an independent investigation had to follow.

The man was arrested for drug-related offences and was taken to hospital where he was assessed as having a life-changing injury, the police watchdog said.

The police officer who tased the man is now subject to a criminal investigation for allegedly causing grievous bodily harm. He was also yesterday served notice of investigation for gross misconduct.

IOPC Regional Director Sal Naseem said: "Having examined a range of evidence including body worn video, witness statements and medical evidence, we have taken the decision that this is now a criminal investigation.

"A criminal investigation does not mean that criminal charges will necessarily follow.

"We understand that many people are concerned about this incident and I want to reassure people that this is being thoroughly and independently investigated."