Rob Knox (right) had a small part in the new Harry Potter film
A man accused of murdering 18-year-old actor Rob Knox in south-east London was an "aggressor acting out of revenge", a jury has heard.
Karl Bishop, 21, of Sidcup, is a man who "carries knives like others carry pens in their pockets", the prosecutor at the Old Bailey said.
The court has heard Mr Bishop claimed he acted in self-defence and said he was attacked by Mr Knox outside a bar.
Mr Bishop, from Carlton Road, denies murdering Mr Knox in May last year.
Rob Knox, 18, of Swanley in Kent, had a part in the next Harry Potter film.
He was stabbed five times outside the Metro bar in Sidcup.
The court had heard Mr Bishop had come off worst in a fight with Mr Knox and his friends the week before the killing, and again earlier that same night, before going home to arm himself with two kitchen knives.
Brian Altman QC, prosecuting, said in his closing speech: "This man was the aggressor and he was acting out of revenge.
"He wasn't under attack - because he had the whip hand. He was the one armed with and using two knives.
"Stabbing Rob and his friends was out of proportion to anything happening to him, so over the top that it cannot sensibly be regarded as lawful self-defence."
He added: "This man carries knives like others carry pens in their pockets, quite happily thinks little or nothing of stabbing others as if it were some occupational hazard.
"Carrying knives is abnormal, it is not permitted, it cannot be done.
"It is not glamorous, it is not normal and it is not allowed. People get seriously injured and people die - as this case all too tragically demonstrates."
Bishop is charged with murder and five counts of wounding with intent to cause grievous bodily harm to five other youths.