28 December 2011 Last updated at 11:50 ET

Lawrence trial: Sympathy warning as judge sums up case

The judge at the Stephen Lawrence murder trial has told jurors to set any emotion aside in their deliberations.

Mr Lawrence, 18, was stabbed at a bus stop after being set upon by a group of white youths in Eltham, south London.

Gary Dobson, 36, and David Norris, 35, deny murdering the black teenager in 1993. The defence says that forensic evidence against them was contaminated.

Summing up, Mr Justice Treacy said "emotion such as sympathy for the Lawrence family has no part to play".

"Equally, anger at the nature of the attack on Stephen Lawrence cannot guide your decision," he said.

The judge told the jury it would be retiring on Thursday to consider its verdicts.

Mr Lawrence's parents Neville and Doreen and his brother Stuart are at the Old Bailey, which has been specially opened during the holiday period for the case.

Mr Justice Treacy said he would cover the attack, the question of contamination, forensics and the defence case in his summing up.

The judge said Mr Dobson and Mr Norris could be found guilty if they were party to Mr Lawrence's killing - even if they did not strike the fatal blow. He said manslaughter should only be considered if jurors found the pair not guilty of murder.

Mr Justice Treacy said scientific evidence found in a 2007 review of the case was "of no value" if it was proved to have been contaminated.

He told jurors the case was "real life, not a detective novel" and it was unnecessary to tie up loose ends.

They should not be affected by the "enormous publicity" the case had attracted, he added.

The judge set out key steps that jurors will need to follow in their route to a verdict.

These include considering whether forensic evidence found on clothes seized from Mr Dobson's and Mr Norris's homes got there via contamination during handling and storage.

The jury must also consider whether the defendants were present at the time of the attack and participated in it.

If at least one member of the group intended to kill or cause serious harm to Mr Lawrence then the attackers would be guilty of murder, the judge said.

But if they intended to cause injury falling short of serious bodily harm, then the group would be guilty of manslaughter.

Mr Justice Treacy then went through the various witness accounts that the jury has heard, including details of any description of the attackers that they gave.

The judge also summarised details of some of the scientific examinations of the clothes seized from Mr Dobson's and Mr Norris's homes, and the garments Mr Lawrence was wearing when he died.

Last week, Mr Norris's barrister, Stephen Batten QC, told the jury that the defendants had been faced with a prosecution outside court from the media since 1993.

Mr Batten urged jurors not to convict the defendants on the basis that if they did not "racism will have won". He said forensic evidence linking his client to the murder was "not safe".

Mr Dobson's barrister, Tim Roberts QC, told jurors that forensic findings presented by the prosecution in the trial did not "fit with the wider picture given by the rest of the evidence".

Mr Roberts said no eyewitnesses had placed his client at the scene of the attack and that traces of blood and fibres belonging to Stephen Lawrence that were found on Mr Dobson's clothing were the result of police contamination.

The trial, which began on 14 November, was adjourned until Thursday when the judge will continue summing up.