Iris Baker has vowed to fight to prove the innocence of her son, who has been jailed for 14 years in Japan for drugs offences he claims he did not commit.

Nick Baker, 32, claims he was duped by a travelling companion after more than 40,000 ecstasy tablets and 2lbs of cocaine were found in a suitcase he was carrying at Narita Airport.

Mrs Baker, 54, from Oaksey near Cricklade, said she felt absolutely numb when she learned about his sentence yesterday.

The father-of-one of Stroud, who was arrested in April last year, was also fined £25,600 at Chiba District Court near Tokyo.

Mrs Baker said: "I just feel that I can't stop and if I stop it is all going to hit me.

"I feel absolutely numb, but I am more worried about how Nick feels. How does my son feel when he knows he is innocent?

"I know he is in a bad state, he is on suicide watch at the moment and has been in solitary confinement for 14 months.

Mrs Baker, a financial controller who is divorced from Nick's father, said her son had not spoken to his partner Beverley or their two-year-old son in the 14 months since his arrest.

She said Mr Baker was not allowed to receive or make any telephone calls from prison.

The only time Mrs Baker has spoken to him was during her visit to the prison in Chiba in March this year.

She said: "I hope now that the British Government will step in and do something to help my son because there is evidence that will prove my son was duped."

Mrs Baker added that her son had been in Japan purely as a football fan to collect World Cup souvenirs when he was arrested on April 13, 2002 in Tokyo.

Mr Baker formerly worked as a chef but had set up his own fencing business.