A friend of two teenagers killed in 1977 has told a court she saw the man accused of their murders with them in the pub where they were last seen alive.

Jackie Thomson, 54, identified Angus Sinclair, 69, as one of the two men she saw with Christine Eadie and Helen Scott at the World's End pub in Edinburgh.

Sinclair has pleaded not guilty to assaulting, raping and murdering the 17-year-olds between October 15 and 16, 1977 between the pub and locations in East Lothian.

Ms Thomson, who was with the girls on the night they went missing and were killed, was giving evidence on the third day of Sinclair's trial at the High Court in Livingston.

She said she and another friend, Tony, had left Christine and Helen in the World's End in the company of two men at about 10.45pm on Saturday, October 15, 1977.

Prosecuting, Lord Advocate Frank Mulholland said Ms Thomson had been shown a series of 12 photographs of men by the police in 2004.

Mr Mulholland said she was shown the images to see if she could identify anyone who was one of the males she saw with the girls in the pub in 1977.

Pointing to Sinclair, he told the court Ms Thomson had identified the accused. He asked: "How sure were you that this person on photo K, Angus Sinclair, was one of the two male persons?"

Ms Thomson replied: "In 1977 he looked quite a lot different - younger than that. It is hard to say because I had seen photos in the newspapers."

Mr Mulholland asked her to answer the question directly, stating: "How sure were you?"

She replied: "I was pretty sure, yeah."

Earlier in evidence, Ms Thomson described the events of the evening of October 15, 1977 when she, Ms Scott, Ms Eadie and Ms Eadie's flatmate Tony had visited about six to eight different pubs. She said the girls had an alcoholic drink in each pub they visited.

Describing their arrival at the World's End just before 10pm, she said: "It was packed, we had to stand. We went to the bar and got a drink. After that me and Tony went to the toilet. When we came back two men were sitting with Christine and Helen."

Ms Thomson said the girls had been "tipsy", but asked if they were "rolling around drunk", she replied: "No."

Ms Thomson left the pub at about 10.45pm, leaving the two girls sitting next to each other, with one of the men on either side of them.

During cross-examination, Ian Duguid, QC, asked Ms Thomson about previous comments she had made to the police concerning the identification of Sinclair.

"Did you say 'I wish now I had never seen the newspapers as I might be recognising his face from that'," he asked.

Ms Thomson replied: "I can't remember saying that."

Judge Lord Matthews asked: "Would that have been what you were thinking at the time?"

Ms Thomson replied it may have been.

Mr Duguid went on to question Ms Thomson further about the night of October 15. "In the course of the evening Helen Scott and Christine Eadie fell out with one another on two occasions?" he asked.

Ms Thomson replied: "Yes."

"One occasion was because Christine Eadie thought Helen Scott was behaving as if she was drunk," Mr Duguid continued.

"She had a drink in her, but she was fooling about," Ms Thomson said.

Earlier, the court heard from Allan Dixon, 56, Ms Scott's boyfriend at the time of the murders.

Mr Dixon told the court he had been in a relationship with Helen for about two years. Asked by Mr Mulholland if the relationship was physical, Mr Dixon replied: "There was no sex involved."

The trial continues.