The evidence against a man accused of killing two teenage girls 37 years ago is "powerful" and "overwhelming", a court has been told.

Lord Advocate Frank Mulholland, prosecuting, was addressing jurors in the trial of Angus Sinclair, who denies raping and murdering Christine Eadie and her friend Helen Scott.

Mr Mulholland told the jury the girls had suffered a "terrifying" death in "horrific" circumstances.

The 17-year-olds were last seen alive at the World's End pub, Edinburgh, on October 15, 1977. Christine's body was found the following afternoon at Gosford Bay, Aberlady, in East Lothian, while Helen's body was discovered a few hours later in a wheat field near Haddington.

Mr Sinclair, 69, is accused of carrying out the attacks with his brother-in-law Gordon Hamilton, who died in 1996.

Mr Mulholland, in his closing speech to the jury, who have been hearing five weeks of evidence at the High Court in Livingston, said parts of the accused's story were "ludicrous".

Mr Sinclair gave evidence this week in which he said he and Hamilton met the girls in the pub and later drove to Holyrood Park in his caravanette, where both men had consensual sex with each girl before they all travelled to East Lothian because he wanted to go fishing.

Mr Sinclair said Hamilton left in the caravanette and he thought the girls were being driven home. He has said they were "alive and unharmed" when he left them.

He told jurors he only found out what happened to the teenagers after reading about it in a news­paper on the Tuesday.

Mr Mulholland told the jury: "My only regret in this case is that Hamilton is not sitting alongside Sinclair in the dock."

He said the suggestion Hamilton could "overpower" both girls on his own was "ludicrous".

He said Mr Sinclair's evidence that Hamilton returned to East Lothian and was "neither up nor down" and that he was "meandering" and not in a hurry to leave the area "does not stack up" and was "devoid of all credibility".

Mr Mulholland said: "In my submission, there's more chance of Livingston Football Club winning the Champions League than this being true."

The court heard nine days of evidence from forensic scientists Geraldine and Andrew Davidson concerning DNA on clothing, including tights and a bra used as ligatures. The Lord Advocate said the analysis, which lasted up to two years and linked Mr Sinclair's DNA to the ligatures, had been a "magnificent piece of work by two world-class forensic scientists".

Mr Sinclair denies the charges against him and has submitted three special defences of incrimination - blaming Hamilton; alibi - saying he was fishing on the banks of the Firth of Forth near Cockenzie power station at the time; and consent to sexual intercourse.

The jury also heard a closing speech from defence QC Ian Duguid, who said the jury essentially have one issue to address in this case: whether the girls were killed by two men or one.

He said: "The evidence points almost irrefutably towards Gordon Hamilton being the killer."

Mr Duguid argued that two pieces of evidence central to the Crown case - surrounding the tying of the ligatures and DNA on Helen's coat - were "fatally flawed".

The QC also told the jury of the "pressure" facing them, arising from almost daily press and TV coverage of the "brutal, merciless murders".

He reminded the jury of the standard of proof required in Scots law and spoke to them about the two verdicts of acquittal in this case, not proven and not guilty.

Judge Lord Matthews is today expected to give the jury his directions in law.