A knifeman lunged towards Harry Potter actor Rob Knox and shouted "who's going to make my day?" before stabbing him five times, a court heard today.

Knox's friend Nicky Jones told the Old Bailey he tried to calm Karl Bishop down as he stood waving a knife outside the Metro bar in Sidcup, Kent, but ended up being stabbed through the hand.

The court has been told 18-year-old Knox was killed trying to defend his younger brother Jamie after Bishop, 21, threatened him with a knife.

Jones described how he, Jamie Knox and other friends had an encounter with Bishop outside a Tesco Express store shortly before the fatal stabbing, in which the defendant brandished a knife and asked: "What are you laughing at?"

He left, the court heard, telling the group: "It's your lucky night, you're not getting done."

Jones said he spotted Bishop at the bar later holding a knife in his right hand, and told him to calm down.

"It was as I stood up that he then lunged towards the group and towards Rob," Jones said. He claimed Bishop, from Sidcup, was shouting "Who's going to make my fucking day?" and that the main target of his threats appeared to be Rob Knox.

Jones said the defendant was "pointing the knife towards him, arms outstretched". After another youth punched Bishop he took another knife out, the court heard.

"It happens really quickly from then," Jones said. "I grabbed the defendant's left hand to try and stop him from swinging the hand round with the knife. I used my right hand to grab his left hand.

"As I proceeded to grab his left hand, he swung his arm over my head and his hand towards my chest. I raised my left hand in defence to cover myself. The knife in his right hand went right through my wrist and came out between my thumb and index finger.

"As I'd been stabbed I put my hand up, turned away and as I turned away Rob moved past me towards the defendant."

Jones, who held up his scarred hand to the jury, said he was left with tendon damage and had since had two operations.

Bishop denies murder and five charges of wounding with intent to cause grievous bodily harm to five other youths, including Jones, claiming he was acting in self-defence.

The case continues.