Speaking publicly for the first time since the development, Tricia Clive told how the new police theory surrounding the case of her son Scott had left her family "stunned" and no nearer ending their torment.

She said: "We do not have enough proof to say that Scott fell in the water that night and without that proof there is still no closure.

"We're in limbo and not knowing what to do. All we want to do is lay Scott to rest."

Scott, an unemployed labourer, vanished on October 10, 2002, after moving from Scotland to Tyneside to start a new life.

Detectives launched a murder inquiry after discovering the 30-year-old, who had been living in North Shields, had been drinking with a man who later admitted stealing his watch and money.

Seven people were arrested but no charges were ever brought.

Scott's body was never found and the mystery devastated his family back in his home town of Stranraer.

Last October, on the fifth anniversary of his disappearance, the family appealed for Northumbria Police to launch a new inquiry.

Tricia called on detectives to do more to publicise the case and appealed for it to be broadcast on the BBC's Crimewatch.

But after launching a fresh investigation, police have told the family that a witness has come forward to say he saw a man fitting Scott's description near North Shields quayside that night.

Tricia said: "They're now telling us they believe Scott fell in the river that night and drowned.

"After five and a half years of believing he had been murdered, we were stunned and just couldn't take it all in.

"It could have happened the way they've said but, after so long, I don't think anyone will ever know the truth.

"We've asked them what happened to his body and they've told us it could have drifted out to sea or been dragged down.

"The police are now offering us a death certificate saying he drowned but we don't want one."

Tricia, 56, said her husband Colin, a 53-year-old bus driver, and their daughters Lynsey, 30, and Kirsty, 23, had initially not wanted to accept the decision.

She added: "The pressure of not knowing and not having a body to lay to rest has been terrible.

"But I don't know what more we can do and I think we are just going to have to live with it.

"If Scott was here now, I'm sure he would tell me to let it go and get on with my life.

"But, although we will never have closure, it doesn't mean we will ever forget about Scott. He will be in our thoughts for ever."

Det Chief Insp Roger Ford said: "Since the initial investigation new evidence has come to light that indicates Scott fell into the Tyne in the early hours of Friday, October 11, 2002.

"Although his body has not been found I am satisfied Scott's death was a tragic accident rather than anything else.

"I hope this outcome at least provides the family with some sort of closure after all this time."