A judge has ruled that the evidence of a key witness in the trial of two men accused of the murder of a PSNI Constable should be allowed to stand.

A male witness known as ''Witness M'' said one of the accused, Brendan McConville, was at the scene half-an-hour before Constable Stephen Carroll was shot dead in 2009.

Defence lawyers argued that ''Witness M'' had lied to the court and had eyesight problems.

The trial judge said he would not exclude the evidence of ''Witness M'' at this stage and would decide later what weight should be placed on the testimony.

The judge ruled the police had breached the relevant code by not holding an identification parade, but he said the police had not acted on bad faith or irrationally and accordingly he would not exclude the evidence at this stage.

The case was adjourned until tomorrow when defence lawyers are expected to apply to have the case against the accused thrown out for lack of evidence.