THE mother of a botanist missing in Vietnam for almost 18 months has started a new search for her son after obtaining further details of the route he planned to take when he disappeared.

Jamie Taggart's mother Jill Mary is in the town where her son was last seen at the end of October 2013 and began leading a new search yesterday after receiving information about the path he planned to take.

She said her son had left details of the route he had intended to follow in his hunt to document undiscovered species of orchid or rhododendron.

It is claimed the area is being searched for the first time due to previous red-tape restrictions.

Greens co-convenor Patrick Harvie and then First Minister Alex Salmond have repeatedly pressed for diplomatic intervention.

The Foreign and Commonwealth Office earlier wrote to the Vietnamese Ministry of Foreign Affairs to raise the profile of the disappearance of Mr Mr Taggart, 42, who runs the world-renowned Linn Botanic Gardens at Cove, Argyll and Bute.

Officials have aided his mother during the visit.

She said: "I have been in Sa Pa for two days. I have been assisted greatly by British embassy staff providing me with an interpreter and arranging talks with officials and witnesses.

"Having seen for myself the formidable terrain and had the opinions of friends, witnesses and officials here, it is devastating to confirm that our son Jamie Taggart did in fact leave the official route to explore an area that was most likely to contain undiscovered species of orchid or rhododendron.

"He then had an unfortunate accident. This could have been due to his keen urge to commence his search immediately (after) he arrived in Sa Pa after 10 hours on an overnight train and a two and a half hour road trip to Sa Pa."

She said that Mr Taggart had left everything except a small knapsack in his room and called a taxi to take him to Tram Ton pass.

"This was at about 9.30 in the morning," she said. "His proposed guide and friend Son was away with a tour and had not received Jamie's email."

She suggested that the probable route her son took had not been explored "due to lack of permits and red tape" but now a new search had been arranged using native Hmong people an the police.

She added: "This is an unusual alliance.

"Funding for the planned search of three days by at least 15 people including food and overnight camping is partly to be paid for by family and friends and the rest by the Vietnamese Police Department."

Mr Taggart went missing after going trekking in October 2013, two days into a plant-documenting trip.The official search was called off in March last year but Mr Taggart's family and friends have raised thousands of pounds to fund continued searches and local investigations.

In October Mr Taggart's father, Jim Taggart, one of the most prominent botanists in Scotland who founded the gardens, called for more information and said: "Someone, somewhere must know something."

Friends and neighbours in Cove and Kilcreggan raised thousands of pounds to help the search for him, and actor Hugh Grant, who has close connections to the area, sent a personal note of support to his family.