Gary Dobson and David Norris, the two men jailed for the racist murder of black teenager Stephen Lawrence, are to appeal against their convictions.

Dobson, 36, who was sentenced to at least 15 years and two months at the Old Bailey last month, has already begun the process, the Court of Appeal confirmed.

It is understood that co-accused David Norris will also seek to appeal, but papers have not yet been lodged at the Court of Appeal.

Norris, 35, was given a minimum of 14 years and three months for the murder, which the trial judge, Mr Justice Treacy, said was a "terrible and evil crime".

He urged police not to "close the file" on catching the rest of the killers after the court heard that a gang of five or six white youths set upon A-level student Stephen in Eltham, south east London, in 1993.

Mr Justice Treacy said the murder was committed "for no other reason than racial hatred".

On the day of the sentencing Mr Lawrence's father Neville told reporters outside court that he hoped the pair would "give up the rest of the people" involved.

His mother Doreen said the sentences were "quite low", but she appreciated the judge's hands were tied and she would now "start moving on".

In court, Mr Justice Treacy called the killing "a terrible and evil crime", and quoted the Lord Chief Justice who said it was a "murder which scarred the conscience of the nation".

Mr Justice Treacy told the pair: "A totally innocent 18-year-old youth on the threshold of a promising life was brutally cut down in the street in front of eyewitnesses 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."

The evidence in the trial could not prove who wielded the knife, but he said that whoever used it had done so with Dobson and Norris's "knowledge and approval".

Neither of them had shown "the slightest regret or remorse" since the murder and they had both lied to the court.

The Metropolitan Police faced fierce criticism of the original investigation into Mr Lawrence's death.

A public inquiry branded the force institutionally racist and claims were made by Mr and Mrs Lawrence's lawyers that some officers were influenced by Norris' former drugs baron father.

The breakthrough in the investigation came when a cold case team of forensic scientists were called in.

They found tiny traces of blood, hair and fibres on clothing seized from Dobson and Norris' homes.

The defence had claimed that the material got there via contamination, but this was rejected by the jury.

During the trial, which began on 14 November, they were shown police surveillance footage from 1994 of Dobson and Norris using racial slurs.

In the film Norris also launched into a violent tirade about how he would kill and torture black people.

As they were led away, Dobson told the jury: "You have condemned an innocent man here. I hope you can live with yourselves."

His mother Pauline called out from the public gallery above: "He didn't kill that man."

Both men continue to protest their innocence. Stephen Batten QC, for Norris, told the court that he maintains he was not there at the time of the attack.

Updated: 20:21, 30 January 2012