Shaw's employer says the conviction was "patently unfair"
The family of a British man jailed in Afghanistan for bribery have insisted he is "completely innocent" and launched a campaign for his release.
Ex-Army officer Bill Shaw, 52, was tried by an Afghan anti-corruption court part-funded by the UK government.
His daughter Lisa Luckyn-Malone said he would be "devastated", adding: "There is absolutely no evidence against him."
Afghan authorities deny his conviction was an attempt to prove foreigners were to blame for corruption in the country.
As well as being jailed for two years, Shaw was also fined $25,000 (£16,185). Reports say his lawyers will appeal against his conviction.
Shaw admits paying for the release of two impounded vehicles in October but insists he thought this was an official payment.
Mr Shaw could spend up to two years in Pul-e-Charkhi prison
The security firm Shaw worked for - G4S - said his conviction - along with an Afghan colleague - was "patently unfair".
A former soldier from Leeds, West Yorkshire, Shaw served for 28 years in the Army and was awarded the MBE.
Now his family have launched a campaign for his release, with two Facebook groups in support of him attracting almost 1,500 members by Thursday morning.
Ms Luckyn-Malone said her father was a resilient man but would be devastated by his conviction.
She added: "It's a complete injustice. He has done nothing wrong.
"My father believed he was making an official payment and his employers backed him up.
"We want to bring him home soon."
Shaw said he believed he was paying a legitimate fine to release two vehicles that were impounded by the national directorate due to licensing irregularities.
He arranged with a man for the cars to be released in return for $25,000.
His lawyer argued in court that the fact that he tried to get a receipt at the time the money was paid and for weeks afterwards proved that he had not intended to pay a bribe.
Shaw also co-operated with authorities, voluntarily attending interviews with investigators, his supporters say.
He also returned to the country after a 12-day holiday in the UK in early January before he was arrested on 3 March.
The BBC's Martin Patience in Kabul says his trial was one of the first cases heard by an anti-corruption court which was set up to help the Afghan government crack down on offenders.
Shaw is now set to be moved to Pul-e-Charkhi prison - a notorious jail on the outskirts of the capital, Kabul - in the coming days.
His lawyer Kimberley Motley said the trial had been poorly conducted and that there would be an immediate appeal.
"For some reason [the tribunal] decided not to follow Afghan law or the UN conventions to which Afghanistan is a party. Furthermore, the presumption of innocence did not exist for him," she told the Guardian.