THE mother of a Scots botanist missing in the Vietnam jungle says she believes he is still alive five months after he disappeared and that he may have stumbled on a drugs trafficking ring.

The search for Jamie Taggart, 42, who runs the world-renowned Linn Botanic Gardens at Cove, Argyll and Bute, that his father founded, has officially been called off.

His mother, Jill Mary, and father Jim are now planning to hire a private investigator.

Mr Taggart left his boarding house in Sa Pa Town to go plant-hunting at the end of October, but did not return from the trip in the forested region.

His mother has spoken publicly for the first time about what she thinks has happened to him since he disappeared.

She said: "I still believe my son is alive. I desperately want a private investigator who is trustworthy, who is preferably Vietnamese or at least someone who can speak the language, to ask the right questions to discover what has happened to Jamie.

"Even if he has chosen to disappear there must be some evidence of that choice, otherwise he must be imprisoned by some work gang.

"I am sure that if this can be instigated we can raise funds for this.

"The Vietnamese government is committed to avoiding detrimental information about the country to be leaked to the West, but it is a notoriously lawless place with slave trafficking and illegal mining and gold extraction and drug trafficking."

Mr Taggart's father said they were now looking at hiring the investigator.

He said: "An extensive search of the area where Jamie went missing on October 30 is now concluded without any trace of him being found.

"We are investigating the possibility of a private detective to try to find out just what happened on the October 30/31 last year."

Friend John Sweeney said: "One of the first things they said was that he may have accidentally stumbled across something he shouldn't have, ie organised drug manufacturing, and got himself into some bother."

Residents in and around Cove has raised thousands of pounds to pay for the search and actor Hugh Grant, who has family connections in the area, pledged a donation and sent the family a message of support.

A series of sightings in four locations have been confirmed in recent weeks by searchers but all date to the time Mr Taggart went missing.

He was last seen on the main Sa Pa Town road heading west and at one stage was trying to obtain a permit to the national park.

He left the town on a motorbike taxi, and was heading towards the mountainous region in north Vietnam, where he was planning to document plants at high altitude.

It is understood arrangements are now being made to recover Mr Taggart's belongings from Vietnam.

Freak snowfalls hampered searchers in December and the hunt was halted. Trekking in some parts of the park was banned because of risk of forest fires.