Prime Minister Theresa May has said she is "deeply disappointed and concerned" about the case of a British academic jailed for life in the United Arab Emirates.
Matthew Hedges, 31, who is accused of spying on behalf of the British Government, was shaking as he was sentenced to life imprisonment in a five-minute hearing at an Abu Dhabi court on Wednesday, his wife Daniela Tejada said.
She said the couple's "nightmare has gotten even worse" as Foreign Secretary Jeremy Hunt threatened the UAE with "serious diplomatic consequences" if leaders do not reconsider.
Mrs May told MPs: "The Foreign Office will remain in close contact with Matthew, his family and his lawyer.
"We will continue to do all we can to support them as they consider the next steps and we will continue to press this matter at the highest level with the Emiratis."
Mr Hunt said consular officials had been in contact with Mr Hedges' family and added he was "deeply shocked" at the verdict, having personally raised the case with the UAE government.
"We will continue to do everything possible to support him," Mr Hunt said.
"I have repeatedly made clear that the handling of this case by the UAE authorities will have repercussions for the relationship between our two countries, which has to be built on trust."
Mr Hedges' wife Daniela Tejada, who was in court during the hearing, said: "I am in complete shock and I don't know what to do.
"Matthew is innocent. The Foreign Office know this and have made it clear to the UAE authorities that Matthew is not a spy for them.
"This whole case has been handled appallingly from the very beginning with no one taking Matthew's case seriously.
"The British Government must take a stand now for Matthew, one of their citizens."
'Mental health deteriorated'
The Middle Eastern studies specialist from Durham University visited the country to research his PhD thesis and was arrested at Dubai Airport on May 5.
His family's representative said he was held in solitary confinement for over five and a half months, during which his "mental and physical health seriously deteriorated".
At the last hearing on October 24, a court-appointed lawyer maintained Mr Hedges' innocence, arguing that the evidence brought forward did not contain anything confidential.
He suggested the court should review the evidence before passing judgment, and the hearing was postponed until Wednesday.
Mr Hedges was released from detention on October 29 and had been staying in Dubai, with an ankle bracelet monitoring his movements.