The foreign secretary, Jeremy Hunt, has promised a review into how his department handled the case of Matthew Hedges, the British academic convicted on spying charges by the United Arab Emirates.

Hedges, who was held in the country for seven months, and his wife, Daniela Tejada, have lodged a legal complaint against the Foreign Office (FCO) and are demanding it do more to get his initial conviction quashed.

Hunt insisted the FCO had been “very effective” in securing a pardon for Hedges, which led to his release last November. But speaking to BBC Radio 4’s Today programme, he acknowledged “we don’t always get things right” and announced an investigation into the case.

“I’ve asked for someone inside the Foreign Office to look independently at what happened to see whether we did do everything we could in that case as quickly as we could,” Hunt said.

But he added: “The important thing is that we got Matthew out. There was an injustice, we made an intervention, we were prepared to put our relationship with the UAE, which is an ally of the UK, on the line, because we said a British citizen has not been fairly treated. And we got him home.”

Tejada, whom Hunt praised as a “formidable” campaigner for her husband, said the FCO was failing to help Hedges clear his name.

She also challenged Hunt’s assertion that the FCO had been “very effective” in the case. “I beg to differ. It took them seven months to get Matt’s release and that took a lot of public pressure and a lot of battling from my side for them to eventually intervene on Matt’s behalf.”

She added: “We feel that they failed to take the appropriate steps in relation to his mistreatment whilst in detention, which was sufficiently severe to amount to torture.

“This is not about compensation. We want them to support Matt in clearing his name. They were able to support him diplomatically to get him released. Now they need to support him to get his name cleared. He’s been accused of being a British spy. So it’s an issue pertaining to the British government as much as it pertains to Matt.”

Tejada added: “He was released on a presidential pardon, which essentially just means ‘you are a guilty man, but we will be so merciful that we’ll release you’. So he is still a falsely convicted spy and that is something that he has to carry with him every day of his life.”

Hedges said: “Our complaint is that the Foreign Office failed to take effective and timely action to secure my release, in particular to the UAE’s false allegation that I was … an MI6 agent.”

He claimed his treatment had left him dependent on medication and put pressure on his marriage.

He said: “It will have a permanent, long-lasting effect. I have strained relations not only with Daniela but also with trying to have a normal life. We’ve had to see a couples counsellor. I’ve seen two psychiatrists, and I’m going to have continual medical assistance for the foreseeable future.”

Tejada also said the couple were seeking the help of the United Nations in clearing Hedges’ name.