By Anna-Louise Taylor
Jamie Knox said his brother was very protective but always happy
When a "madman" armed with knives threatened his younger brother outside a bar in south-east London, teenage actor Rob Knox stepped in to protect him.
But the "courage and sense of duty" he felt when he waded into the brawl where five others were also stabbed last May cost the 18-year-old his life.
Rob Knox was "living the dream" having played the part of Marcus Belby in the film Harry Potter And The Half-Blood Prince, his father Colin Knox said at his funeral.
"Rob loved the part of Marcus Belby.
"He loved being part of the international iconic story of Harry Potter."
The "big teddy bear", from Sidcup, was "loved by everyone" and "kind and thoughtful", his family and friends said.
His younger brother, 17-year-old Jamie Knox, told the Old Bailey his brother was very protective, but "he wouldn't do anything unless he felt it was necessary".
But his decision to intervene when 22-year-old Karl Bishop confronted Jamie saw him become the 14th teenager to die violently in London in a spate of killings in 2008.
Karl Bishop is a man who "carries knives like others carry pens in their pockets", Brian Altman QC, prosecuting, told the trial.
Bishop told the court that he had been an angry child, and was expelled at the age of 14 when he got in trouble with the police.
He was jailed in May 2005 for slashing two youths' faces and spent nearly two years in prison.
A week before the fatal stabbing Bishop had been involved in two altercations with Rob Knox and his friends at the Metro Bar in Sidcup.
The prosecutor said that that night Bishop had accused people at the bar of stealing his phone.
Bishop had tried to search Rob Knox's pockets for it, but Rob refused to let him.
Bishop then punched Rob's friend Dean Saunders, 18, (who was also later stabbed) and the group retaliated.
Rob Knox "thought the world of Jamie", the court heard
Bishop ran away, only to return with a piece of wood demanding a fight.
With thoughts of revenge, he was heard to make a chilling prediction: "I'm going to come back next week and someone's going to die."
A week later, on the night of 24 May, Bishop, who was drunk and had been smoking cannabis, turned up at the Metro Bar.
Bishop was not allowed inside, and got into another punch-up outside with another man, came off worst and fled.
Humiliated, he went home, where he said a "red mist" descended upon him and he picked up two kitchen knives.
"I took two, because two is scarier than one and I was angry at the time.
"I had just been beaten up - twice in two weeks," he said.
"My assumption was that it was the same people as it was the same place, so I was quite angry."
He denied that he planned to use them - saying he just "wanted to scare whoever was down there".
On his way back to the bar he then threatened another youth, Nicky Jones, 19, who was also later stabbed, outside a nearby Tesco Express.
Jamie Knox saw this and tried to intervene but Bishop then turned on him.
Another of Rob's friends, Callum Turner, 19, drove his car between Bishop and Jamie, but Bishop then threatened Callum with the knife too.
A message got to Rob Knox, who was in the bar, that his brother had been threatened with a knife and he went outside.
Bishop's claims he acted in self-defence were dismissed by the jury
Mr Altman said: "There stood the defendant outside, brandishing his two knives.
"Not surprisingly, a crowd mushroomed in size around him.
"Rob Knox thought the world of Jamie and it is quite clear and entirely understandable that Rob must have believed, on good grounds, that Jamie was in danger."
Mr Altman said: "Unfortunately his courage and sense of duty were to cost him his life."
The court heard that Rob asked Bishop: "Why did you pull a knife on my brother?"
Bishop then called out: "Who's going to make my day?"
But Rob replied: "I am not fighting you with knives, put the knives away."
His friend Tarik Ozresberoglu said: "He went over there like a man, with nothing in his hands, not with knives."
Bishop warned he "would stab anyone who came near him", Mr Altman said, but when he put the knives away, another youth punched him.
Rob Knox's friends who gave evidence said then Bishop became a "madman".
Bishop claimed he acted in self-defence - that the group of 10 youths that surrounded him attacked him.
"There was no other option. They ran at me, they attacked me.
"Then as they kept running at me the knife was catching them while they kept running into it.
"You wouldn't think people would run at someone who's got a knife.
Many of Rob Knox's friends paid tribute to him after his death in Sidcup
"I was just trying to get away."
In the melee Rob Knox rugby-tackled Bishop, who stabbed him repeatedly, severing a main artery.
Bishop's other victims were stabbed in the chest, legs, arms, face and hand, one of them suffering "significant spinal damage".
Mr Altman said Bishop's stab attack was "out of proportion to anything happening to him, so over-the-top it cannot be regarded as lawful self-defence".
The jury agreed, and Bishop, of Beaver Lodge, Carlton Road, Sidcup was convicted of murder.
He was also found guilty wounding Dean Saunders with intent to cause him grievous bodily harm.
Bishop was found not guilty of wounding Tom Hopkins.
He will be sentenced on Thursday.