A fitness instructor left a young man brain damaged after stabbing him in the head in a suspected drug feud, a court heard.

Jahleel Nafiu, 22, of South Norwood, is accused of stabbing Sydney Annan, also 22, in the head with a six-inch kitchen knife after the pair met up to smoke cannabis.

Mr Annan suffered "catastrophic" injuries and is still in hospital to this day after the attack at Brunel Close, Upper Norwood, on October 11 2012.

Mr Nafiu denies attempted murder and grievous bodily harm with intent.

Victor Temple, prosecuting, said Mr Nafiu, who used the street name Factor, texted Mr Annan, who called himself Max, earlier in the day saying he had some good quality cannabis.

Mr Annan, who has previous convictions for drug dealing, theft and possession of a knife, met Mr Nafiu at the Queens Hotel, in Church Road then made their way to Brunel Close, the court was told.

Yesterday the Old Bailey jury heard how Mr Annan was stabbed through his left eye socket, into his brain through to the back of his head, and above his right eye and shoulder.

The jury was not told what the alleged flashpoint of the attack was, but were told the incident had obvious drug connections.

Mr Temple said: "Mr Annan suffered catastrophic and life-threatening injuries.

"He suffered brain damage and behaves inappropriately, such as laughing out loud sometimes.

"The Crown say that this defendant attempted to kill Mr Annan by stabbing him multiple times to the head and upper body."

Mr Temple added Mr Nafiu, who did casual work as a fitness instructor at Wimbledon Leisure Centre, will claim he acted in self-defence and it was Mr Annan who had the knife.

But the jury was told the severity of Mr Annan’s injuries went beyond self-defence.

The court was told nobody witnessed the attack but a neighbour saw Mr Annan lying in the doorway of the block of flats in a pool of blood, banging the knife repeatedly on the ground.

Mr Temple said it was probable Mr Nafiu got hold of the knife during a struggle with Mr Annan.

The jury was shown CCTV images, alleged to be Mr Nafiu running from the scene of the stabbing.

Mr Nafiu later went to St George's Hospital to get treatment for cuts to his hand, which he said were sustained after picking up a broken plate.

Mr Temple told the court the injuries were from the knife used to attack Mr Annan.

The trial continues.