The Supreme Court has set out principles to guide trial judges on the treatment of evidence in trials of sexual offences involving more than one complainant.

The points are set out in a judgment rejecting an appeal by a man jailed for seven-and-a-half years for raping two women in his Sligo apartment in 2014.

The court's main judgment concluded the evidence of each of the two women was admissible in respect of each charge.

Clement Limen from North Court, Quayside, Sligo, had appealed his conviction for raping the two women at his flat on 2 June 2014 and of one count of sexual assault.

Limen, who is in his forties, was sentenced in December 2017.

The two women who were in their 30s were invited by Limen to a party along with ten others after they met him in a nightclub. They were the last to leave and remembered him giving them a drink which was described by the women as "funny" and "strong". They also shared a joint.

Both women said they then remembered nothing until they woke up.

One woke on the living room couch to find Limen raping her. She pushed him away and found her friend in a bedroom who said the same thing had happened to her.

Both fled the apartment without their shoes and were collected by a husband of one of the women who took them to a garda station.

 Limen was arrested shortly after and denied raping either of the women.

Limen's lawyers did not seek separate trials and the trial proceeded on the basis the case essentially involved two complainants and one incident.

The Supreme Court agreed to hear his appeal over his conviction arising from issues raised by his lawyers over how the trial judge handled certain issues, including their objections to prosecution counsel asking the jury, in her closing speech, to consider elements of testimony of each complainant had "striking" similarities and there was no suggestion of them colluding with each other.

In her judgment, Ms Justice Iseult O'Malley, noted toxicology reports found nothing suspicious in the liquid remaining in glasses taken from the apartment. 

She set out principles concerning the treatment of evidence in trials of sexual offences involving more than one complainant, including the admissibility of "misconduct" evidence, "similar fact" or "system" evidence and the proper role of corroboration rules in such trials.

Those principles include that a judge may order separate trials if of the opinion it would be unfair to proceed with one. Decisions were also subject at all times to the overriding requirement to ensure a fair trial.

Judge O Malley held the evidence of both women was admissible in respect of each charge against the man. The best way of describing what happened in the apartment was that adopted by defence counsel when he said the case involved two complainants and one incident, she said. While not categorising that as a legal concession, it was an "apt description".

The trial judge's instruction to the jury to consider each count separately could only have been seen as in the interest of the defence, she said.

She did not accept the prosecution's use of the words "striking similarity" would have conveyed any special legal meaning to the jury.

In a concurring judgment, Mr Justice Peter Charleton analysed how a path for general application can be found for future trials of multiple allegations.

In this case, there was nothing to suggest the trial judge's directions were anything other than favourable to the accused, he said.