By Phil Mercer in Bangkok

An English language teacher from Sussex has been convicted of smuggling 4kg of heroin after being arrested at Bangkok's Don Muang airport last October.

Julian Gilbey arrived at court in chains, flanked by armed guards.

He made the short journey from Bangkok's notoriously tough Klong Prem jail on a crowded prison bus.

The 35-year-old from Sussex was lead into a cage below the courtroom with dozens of Thai prisoners, who shouted to relatives through two sets of bars.

An hour later, the former English language teacher was escorted into court, high on the ninth floor of Bangkok's imposing Central Criminal Court.

He was dressed in light brown prison fatigues and stood barefoot alongside four co-defendants - a Dutchman, a Thai woman and two men from Nepal.

Consular officials will visit Gilbey in the next few days

They were caught trying to smuggle more than 4kg of heroin from Thailand to Taiwan last October.

There are no juries in Thailand and the verdict was read by a single judge.

All four men were given life sentences. Gilbey was spared the death penalty.

The judge told him a confession he made to the police during his arrest at Bangkok's Don Muang airport last year had convinced him to impose a life sentence instead.

The woman was acquitted.

During his trial, the British man claimed he was tricked into carrying the drugs by a criminal gang. He said he thought he was smuggling diamonds.

Drug offences of this scale usually carry a mandatory death sentence.

Clemency

Last year more than 50 people were executed by machine gun here in Thailand.

Life sentences handed down by courts here in Thailand amount to 99 years behind bars without parole.

We are concerned that he will be expected to serve a life sentence in a prison notorious for its appalling conditions

Ian Acheson, Prisoners Abroad

Gilbey's lawyer has said he will take his case to the Appeals Court in an attempt to have the punishment overturned or reduced.

If that fails, petitions can be made to the Supreme Court and finally to the King of Thailand, who has, in the past, granted clemency to foreign prisoners.

Fergus Auld from the British Embassy in Bangkok told the BBC the UK Government would not seek to have Gilbey's sentence reduced or reviewed:

"There'll be no representation from Britain to influence the judicial process. It's a matter for the Thai authorities," he said.

'Inedible'

Consular officials, however, plan to visit Gilbey within the next few days.

If the various avenues of appeal prove unsuccessful, Gilbey can apply in seven years time to serve out his sentence in a British jail under a prisoner transfer agreement.

Life in an overcrowded Thai jail can be brutal. Earlier this year the Corrections Department admitted the country's prisons were plagued with human rights violations by warders.

These included torture, extortion and receiving sexual favours from inmates' wives and daughters.

The executive director of the charity Prisoners Abroad, Ian Acheson, said he was worried about the conditions Julian Gilbey would be forced to endure.

"Although we are relieved he was not sentenced to death, we are concerned that he will be expected to serve a life sentence in a prison notorious for its appalling conditions."

One European prisoner at Bangkok's maximum security Bangkwang jail said life inside was a nightmare.

"We have one meal a day - a small plastic bag of rice with an inedible stew that is not enough to sustain an animal."