Four-year-old Ryan Aggett has only seen his parents once since he was prised out of their arms in a Thai prison.

His parents, Jody and Kristin, are currently languishing in a Bangkok prison after being arrested in a police raid in 2001.

Their family said they were charged unjustly with manufacturing ecstasy and sentenced to death a sentence that was later commuted to life imprisonment.

Ryan was born in the jail on January 1, 2002 but was taken from his parents just ten weeks later.

He now lives with his grandparents, Lorna and Tony Aggett, in Wootton Bassett and last year visited his parents for the first time.

Mr Aggett, 54, originally from South Africa, said: "Ryan knows he's got a mummy and daddy and that they're in Bangkok.

"He's been to see them but because he's still so young he hasn't asked many questions."

Last year's trip was the third time Mr and Mrs Aggett have been to see their son since 2001 and Mr Aggett hopes to go again in June.

"I was hoping to go in April but it's a question of finding the money and work is very busy," he said.

The family communicate by letters but there is a faint hope that inmates in the prison may soon be issued with phone cards. "That would give us voice contact," said Mr Aggett, who works for Ford in Swindon.

"That would be amazing, especially for Ryan because he just loves talking on the phone."

The family are continuing to fight for their son's release and are waiting for a supreme court appeal.

"It's been very tough for everyone particularly Jody's twin sister who lives in Johannesburg but you've just got to keep going," said Mr Aggett.

"Ryan is an absolute star and we can't imagine life without him. However the day will come when we have to hand him back to his dad because we're positive we're going to be successful and that he will be released.

"There will come a time when we have to tell Ryan all about it as well. He's got to know what's happened but in the meantime we'll keep battling."

Mr Aggett said his son was doing fine and had become the first foreigner to help in the pharmacy wing of the hospital. He said he had helped teach some of the guards English and had a strong nature.

"He's trying to make the most of a rotten situation," added Mr Aggett.

At the time of their arrest Jody and his wife had been staying rent-free in a building containing a travel agency on the condition that they opened and closed the business each day.

But the owner of the agency had been manufacturing ecstasy at the premises and Jody and Kristin were charged with them and sentenced in 2003.

Mr Aggett said his son was under considerable stress when he signed a confession and that alongside it he had written I don't understand any of this'.

Their cause is being backed by the group Fair Trials Abroad.

Group lawyer Sabine Zanker said: "We believe the judgement lacks reasoning.

"The conviction of the estate agent and his girlfriend was based on evidence of a police informer who did not mention Jody or his girlfriend.

"There is no evidence to link Jody to the crime. He was not originally allowed access to an interpreter and in police interrogation he was forced to sign a confession. They have very harsh interrogation methods that would make me sign anything."