Mr Fyfe spoke of the effort the family has put in since their son's death to gather further evidence in an attempt to have the police reopen their investigation.

He said: "The McLeods have tried endlessly to ascertain what happened to their son that night but there was never any evidence about an assault at the harbour where he tragically drowned.

"It would now appear that this witness saw an assault at the harbour, so this is vital evidence.

"This was always the missing link and I would hope that the police will now reinvestigate the case and the McLeods hope that criminal charges would follow from that."

Violent crime

Mr Fyfe added that he had written to the police, but was still awaiting a reply.

However, he said he was confident that, in light of the strength of the new evidence that they would reopen the inquiry.

"If they did not," he said, "we could always ask for the Fatal Accident Inquiry to be reopened and I can also make a claim for criminal injuries compensation because I think we can now show that Kevin died as a result of a violent crime."

He said the family was unhappy with the original police inquiry, in particular that no door-to-door inquiries had taken place and that no senior officer had been involved in the matter.

"They will always hope that some witness might come forward, and now that has happened, I think they're overjoyed that there is evidence to this effect and that, eventually, criminal charges might follow," he added.