A SCOT may face deportation from Thailand after donning the uniform of a rebel army and joining the guerrilla war against the military government of neighbouring Myanmar.

David Fisher, a former public health officer from central Scotland, had been living in Thailand when he joined the Karen National Liberation Army, an ethnic Myanmar rebel group, in its fight for autonomy against the country's military government.

The 47-year-old was photographed in Myanmar, formerly known as Burma, near the Thai border as the Karen ''freedom fighters'' celebrated their annual Martyrs Day.

The revelation comes in the wake of a similar story about a 19-year-old Swedish woman, known as Vanja, who is also helping the Karens and was pictured in a uniform with a rifle.

The Scot said he did not take part in any fighting, and described his work as a humanitarian mission to aid those who suffered wounds or went down with malaria in the jungle war.

''I just do my duty for humanitarian reasons. I do not want to get involved in the fighting. Both soldiers and villagers here need first aid service, medical treatment, and supplementary health service,'' he said.

Mr Fisher said he had set up the clinic two years ago and had never been involved in conflict of any kind. ''As for being armed, KNU officers allow me to have a gun for self-defence and emergency cases only,'' he said.

The dramatic photograph is thought to have been taken earlier this week after the Thai authorities, anxious to improve relations with Myanmar's harsh military government, had imposed a ban on foreign journalists entering sensitive zones along the Thai-Myanmar border.

This followed reports that the Myanmar military had systematically raped and murdered women of the Shan nation, a Myanmar minority fighting the Rangoon government.

Mr Fisher was photographed in a medical centre in a camp just across the Myanmar border with Thailand, opposite the northern Thai town of Mae Sot.

The Karens remain aggrieved about the deal being reneged on after being promised autonomy by the British when they left. Control of their lands was handed to the Burmese, and discontent has been rife since.

During the 50-year guerrilla war, the Karens claim that their people have suffered a series of atrocities.

Thousands of ethnic Karens have fled to neighbouring Thailand to escape the decades-old fighting between the guerrillas and government soldiers, who are mostly Buddhists.

The Karen National Union is the main rebel group in the area, with about 170 guerrillas living in the camp at Tak where Mr Fisher is stationed.

The Thai government is now trying to establish how Mr Fisher entered Myanmar in the first place, and is also investigating the status of Vanja, who arrived in the country as a tourist but stayed on to fight for the guerrillas, and has risen to the rank of sergeant.

''If Mr Fisher entered through Thailand he can be summarily deported for breaking immigration regulations,'' a Thai immigration policeman said.

A spokesman for the Karen National Union, the ruling political body of the Karen insurgents said: ''Neither the Scot nor the Swedish girl is involved in any fighting. They have offered aid and we have accepted it.''