For 15 months, detectives investigating the disappearance of businessman Andrew Ramsay have been baffled by what became of him.

The middle-aged father of two was bundled into a car near his home in Glasgow in February last year by two men claiming to be police officers and has never been seen since.

There were few clues, although the lack of any ransom demand led them to believe his abduction may have been some kind of vendetta. Another theory put forward was that he staged his own disappearance.

Yesterday, police revealed that they had found his skull, putting an end to any hope they had of finding him alive.

His head was caught in the nets of fishermen off the Isle of Cumbrae in the Firth of Clyde on April 5 and handed over to police. Forensic tests have now confirmed the skull to be that of Mr Ramsay.

Police were able to say it had been in the water for some months and that there was no evidence, at this stage, to suggest he had met a violent end. It was unlikely that a body would remain intact after such a long time in the water, they said.

But the scant remains of the accountant have offered them few clues as to what happened to him or why.

Detective Superintendent William Prendergast said that, until now, he had never given up hope that Mr Ramsay would be found safe and well.

He was “deeply saddened” to have to inform Mr Ramsay’s family of the news, he said.

Mr Prendergast said the investigation would be stepped up once more, but that it would remain an abduction and not a murder inquiry.

He said: “This is still a mystery. There are still questions to be answered here.”

The skull will undergo further forensic tests. No further searches will be carried out, as the remains were found in open water.

As details of twice-married Mr Ramsay’s past emerged after his disappearance, so speculation increased as to what might have happened.

It turned out he had been interviewed by HM Customs as part of a probe into money-laundering at a company which once employed him and there were reports that he was due to appear in a high court case as a witness in a fraud trail.

Rumours of the reasons for his abduction intensified when his former girlfriend, the Belgian model and singer Marijke Vannut, was quoted as saying that he “owed a lot of people a lot of money” and that, when they were together, he was always looking over his shoulder.

Mr Ramsay, who was going through a divorce when he was abducted, had worked in Saudi Arabia, Hong Kong and Europe, where he lived in Belgium.

Mr Prendergast once described him as a “man who knew his way about the avenues of life”.

He had a number of failed companies, including Golden Miles, of which he was a director and which he operated out of the same property as a well-known Glasgow brothel.

Yesterday, police spoke out to deny reports that Mr Ramsay had been due to appear as a witness and added that he was not known to them before his abduction.

Mr Prendergast said: “Andrew had been interviewed on several occasions by officers from HM Revenue and Customs. There was never any trial set in relation to those interviews.

“As to whether that has anything to do with his disappearance or not, there’s no evidence to suggest that.”

He added that Mr Ramsay had “no criminality in his history” and had been well liked.

“He was good in conversation; he could come into a room and join into company,” Mr Prendergast said.

“So with this kind of outward personality, we were hoping that we would trace Andrew.”

Police now say that, aside from knowing that he is dead, they are no further forward in the investigation.

Mr Ramsay was taken on the street on February 22 as he walked to his home in Cardonald from the pub with his girlfriend, Beverly Sinclair.

As they arrived, two smartly dressed men, purporting to be police officers, told him he was under arrest and took him away in a dark-coloured car.

Despite a Crimewatch appeal, there have been no witnesses and no confirmed sightings.

The hunt will continue for the two men who abducted Mr Ramsay.