The family of a retired British businessman who has been granted bail after being extradited to the United States over arms dealing charges plan to visit him as soon as possible, his wife Elaine has said.

Elaine Tappin said she was relieved and "grateful for the judge's humanity" after her 65-year-old husband Christopher was granted bail in Texas.

His family must now pay $50,000 (£31,026) to secure his release on a $1 million bond (£620,527) later this week.

Mrs Tappin, 62, of Orpington, Kent, said her husband had been "unnecessarily locked up" for more than eight weeks and "abandoned by the authorities in his own country".

By releasing him on bail, the judge had given him an opportunity to challenge the allegations made against him, she said.

He faces up to 35 years in jail if convicted of trying to sell batteries for surface-to-air missiles to Iran.

In a statement released to the Press Association, Mrs Tappin said: "We are so relieved at Chris's release and are grateful for the judge's humanity in granting him bail.

"Chris has been unnecessarily locked up for over eight weeks in the middle of the New Mexico desert, abandoned by the authorities in his own country, without even having had a chance to clear his name.

"At least now he can begin to examine the prosecution's case with his lawyers and prepare to challenge at trial the allegations which he denies."

She added: "We have not yet had the opportunity to speak to him but we are making arrangements to visit him as soon as we can."

Mrs Tappin went on: "I would like to thank all those many people, most of whom we do not know, who have written to us, to their MPs, to the Home Office, and spoken out about Chris's ordeal.

"Their support has been invaluable and of great comfort to us as we waited day by day for his bail to be granted.

"We truly hope this support can be channelled into forcing a change in the extradition laws.

"British citizens should not be packaged off thousands of miles away from home without having seen the evidence against them, without having been able to challenge the decision on jurisdiction for trial in the British courts, and before the country who seeks them is ready to go to trial to avoid prolonged periods of unnecessary pre-trial incarceration.

"Extradition without these safeguards is, quite simply, a betrayal of justice."

Tappin will be released from the Otero County detention centre in New Mexico either on Tuesday or Wednesday, his US lawyer Kent Schaffer said, after Judge David Briones set the bond.

Tappin, the former president of the Kent Golf Union, was told last month that he must remain in custody while he awaits trial over the state border in El Paso, Texas.

He denies the charges.

The case fuelled the row over the fairness of the extradition treaty between the UK and the US.

Attorney general Dominic Grieve QC said Tappin's extradition highlighted problems with the treaty which were not "readily curable", warning that many Britons were left uneasy when faced with the seemingly harsh and disproportionate sentences in the American justice system.

Other critics of the 2003 treaty, including deputy prime minister Nick Clegg, have described it as "one-sided", but an independent review by retired Court of Appeal judge Sir Scott Baker last year found it was both balanced and fair.

Tappin's extradition follows an investigation which started in 2005 when US agents asked technology providers about buyers who might have raised red flags.

Those customers were then approached by undercover companies set up by government agencies.

Briton Robert Gibson, an associate of Tappin who agreed to co-operate, was jailed for 24 months after pleading guilty to conspiracy to export defence articles.

Gibson provided ICE agents with about 16,000 computer files and emails indicating that he and Tappin had long-standing commercial ties with Iranian customers.

American Robert Caldwell was also found guilty of aiding and abetting the illegal transport of defence articles and served 20 months in prison.