Jamie has been missing since November of last year, and this week his father, Dr Jim Taggart, attacked the ‘embarrassing’ response by the Foreign and Commonwealth Office (FCO).

Dr Taggart believes local police in the Sapa area in Vietnam are withholding information about the 42-year-old volunteer firefighter, who went missing on a plant-hunting expedition in the mountainous Hoang Lien national park.

He said: “We have someone missing for four months, known to be missing the day he did not return to the hostel – they had his passport, they knew who he was and they knew he was a missing person, and they did nothing.

“I don’t know what happened but I suspect the police may know more than they are letting on.

“Apparently people do disappear in that part of the world.

“There is just no evidence of what happened. The police obviously told no one, though they had his passport. That would be a big concern for anyone visiting there.” Dr Taggart said it was ‘improbable but not impossible’ that Jamie was still alive, and the family needed to know what had happened.

He added: “It should be a matter of public interest. The FCO’s failure to act is ‘embarrassing’ as it had taken several weeks for them to put posters up in the area, and local press did not carry the story.

“Nothing was publicised at all, we have been in touch with several people in Sapa and they did not know about anyone being missing.

“They say it is a place they recommend as entirely safe for British citizens.

“The Foreign Office should come clean as to what they know or don’t know. The first thing they should do is interrogate the police.” Thousands of pounds has been raised to help the search for Jamie and teams have combed the remote area in vain.

Dr Taggart said national park director Luong Van Hao had been ‘amazed’ no trace had been found.

He said: “Mr Hao said ‘We will find him, because he could only go so far in that country in a day’.

“There is no sign of a body – it is very hard for a body to disappear absolutely without trace.” An FCO spokesperson said this week: “We have been providing consular assistance to James’ family since we were made aware of his disappearance, which includes providing them with all information that has been passed to us by the Vietnamese authorities in relation to James’s case.

“We will continue to provide consular support to the family and to liaise with the Vietnamese authorities.

“We keep our travel advice under constant review and the safety of British nationals is our primary concern.” But an email sent to Dr Taggart blamed the delay in the embassy being informed on ‘local Vietnamese procedures’.

Dr Taggart has asked the public to contact key politicians, asking for the FCO to take action and more pressure to be put on the authorities in Vietnam.