DUBAI/LONDON (Reuters) - A British academic charged with espionage in the United Arab Emirates has been temporarily released until his next hearing on Nov. 21, his wife said on Tuesday.

Matthew Hedges, a 31-year-old doctoral student at Durham University, has been held since May 5, when he was arrested at the Dubai airport after a two-week research visit. He was formally charged this month with spying on the Gulf state, where he has been held in solitary confinement.

Hedges was released on Monday and will be subject to constant monitoring until the November hearing, said his wife, Daniela Tejada, adding that they were not notified in advance that he would be released.

“I of course welcome this development. However, I cannot allow myself to get too excited by this information as Matt is not fully free yet,” she said in a written statement.

Reuters earlier reported, citing sources, Hedges had been released on bail.

The BBC reported Hedges has been released without his passport, told to remain in the UAE until the next hearing, and must wear an ankle monitor.

A UAE government spokesperson could immediately be reached for comment outside working hours.

A spokeswoman for Britain’s foreign office in London said: “We are monitoring developments closely and have made the Emirati authorities aware of all our concerns. We continue to do everything we can for Matthew and his family.”

The UAE’s Federal Court of Appeal last week postponed hearing his case until Nov. 21 to re-examine the evidence.

The country’s attorney general has said Hedges was charged with spying for a foreign state, without naming it, and jeopardizing the military, economic and political security of the country.

More than 120 academics from around the world have issued a petition urging UAE authorities to release him.

According to Durham University’s website, Hedges is a doctoral student in the School of Government and International Affairs whose research interests include civil-military relations, political economy and tribalism.

Last year, he co-wrote an article in an academic journal on the Muslim Brotherhood and the Gulf Cooperation Council, of which the UAE is a member.

The UAE is a tourism and trade hub for the Middle East, but tolerates little public criticism of its ruling families or policies and staunchly opposes the Islamist ideology of the Brotherhood.