James Mawdsley, 26, from Lancashire, was arrested in the city of Tachilek in north east Burma, also known as Myanmar, on Tuesday.

BBC News' Philippa Young: Disquiet expressed at speed of trial

It was the third time he had been arrested in the country, in which he served a jail term last year, and from which he has been deported twice.

This time, Mr Mawdsley was accused of carrying hundreds of pro-democracy leaflets and entering the country illegally.

The British Embassy in Burma said that the authorities had informed it that Mr Mawdsley was sentenced to five years for violating the immigration law and seven years for the publications law, to serve consecutively.

Mr Mawdsley was arrested close to the Thai-Burmese border

Burma's military regime also confirmed that a five-year sentence imposed against him last year for illegal entry, then suspended when he was freed after three months, had been reinstated.

An embassy spokesman said: "We are unhappy with the way the case has been handled, and we did not have access to Mr Mawdsley before the trial took place."

Mr Mawdsley also holds Australian citizenship. Both the British and Australian embassies are still seeking consular access.

Third arrest in Burma

David Mawdlsey explains why his son returned to the country after being imprisoned and tortured

Mr Mawdsley has been deported twice before for his involvement in human rights protests in the country, which is under military rule.

He telephoned his father, David, from Thailand last week and pledged to continue "his human rights campaign against the military regime".

David Mawdsley, 56, of Kensington, west London, said on Thursday that his son "just can't turn his back on it."

He told BBC Radio 4's Today programme: "He returned because he knows what's going on there, he's not a coward, he believes in justice, he believes in human rights and he believes in democracy."

He added that his son first heard about the situation in Burma when he met refugees in New Zealand four years ago.

He took a job in Burma teaching refugees English, but became committed to the cause when the military burnt out the school at which he worked.

Mr Mawdsley's mother, Diana, spoke of her son's great spirituality and sense of humour.

She said: "The governor of Insein prison asked him last time if he was lonely in solitary and he told him: 'No, I have many friends - the mosquitos and the bedbugs'."

Dissidents urge uprising

Mr Mawdsley's sentence comes as dissidents are urging Burma's people to rise up against the military regime on 9 September, or 9-9-99, seen as an auspicious date in the country.

The government has acknowledged arresting nearly 40 people in recent weeks. But Mr Mawdsley is the only foreigner who has been arrested.

He served 98 days of a five-year sentence at Ragoon's notorious Insein Prison, prior to being deported in 1998.