It took less than 30 minutes for Stephen Lawrence's killers to be sentenced for their "terrible crime" at the Old Bailey today.

Mr Justice Treacy told Gary Dobson and David Norris that the murder of the black teenager in 1993 was "committed for no other reason than racial hatred."

He said: "The murder of Stephen Lawrence on the night of 22 April 1993 was a terrible and evil crime. Recently the Lord Chief Justice described it as a 'murder which scarred the conscience of the nation'.

"A totally innocent 18-year-old youth on the threshold of a promising life was brutally cut down in the street in front of eye witnesses by a racist thuggish gang.

"You were both members of that gang. I have no doubt at all that you fully subscribed to its views and attitudes.

"You did not know Stephen Lawrence or Duwayne Brooks. Neither of them had done anything to harm, threaten or offend you in any way, apart from being black and making their way peaceably to the bus-stop on their way home.

"At least one of your group was armed with a lethal knife that night. I am sure you were aware of that."

Mr Justice Treacy referred to the the Footscray tapes, the undercover surveillance videos made by the police in 1994 and which showed more than just racist tendencies amongst the gang.

"They reveal not only violent racist attitudes but also a casual and accepting attitude to the carrying and use of knives," he said. "They reveal a group acceptance of the use of knives to threaten or harm black people.

On the attack itself, the judge emphasised how it was driven by group loyalty.

"A racist taunt, followed by a group charge towards the two young black men, and then the swallowing up of Stephen Lawrence, surrounded and put to the ground by all of you, shows a deliberately concerted attack.

"A knife was used to stab him with blows aimed to vulnerable parts of the body: once when he was upright at the start of the attack; the second when he was on the ground whilst the rest of you were gathered round aiming blows or kicks to put him or keep him on the ground.

"The evidence does not prove so that I could be sure that either of you had a knife, but the person who used it did so with your knowledge and approval.

"The attack lasted in the region of 10 seconds and then the whole group moved off together as one making its escape. I take the view that, in the circumstances, it does not matter that the knife was not in your hands.

"The cohesive nature of the group tells its story. It is not as if, for example, one person unexpectedly did something that no one else expected or approved of. You, Dobson, repeatedly lied to keep Norris's name away from the police, a clear example of group loyalty.

"Stephen Lawrence is not the only victim of this crime. His family, (two parents, a brother and a sister), whose victim impact statements I have read, have been most grievously affected. So has his friend Duwayne Brooks. Of that I have no doubt.

"Neither of you has shown the slightest regret or remorse. Each of you has lied to the court. I do not punish you for that, but this is not a case where there is any mitigation available for contrition."

Turning to the length of sentence, Mr Justice Treacy told the pair he was restricted by law to pass a sentence that reflected their age at the time of the crime, which he acknowledged may not be to everyone's approval.

"It may be, therefore, that the resultant sentences are lower than some might expect, but the law as laid down by Parliament must be applied and I am constrained by it."

He added: "The gravity of this case is in my view of a different order from, for example, a murder committed by one individual upon another as a result of some sudden quarrel.

"There was a degree of general premeditation; it was a racist crime driven by hatred; it involved a gang of like-minded attackers; a lethal weapon was employed and known in advance to be carried; the victim was completely blameless and helpless.

"The high level of public interest in this case is at least in part a reflection of the abhorrence felt by right-thinking people at the nature of this crime. This, too, should be reflected in the sentence.

"In each case, and as a reflection of the fact that the offender was under 18 at the time, I must impose a sentence of Detention at Her Majesty's Pleasure. This form of sentence is, for practical purposes, the same as a life sentence passed on an adult."