LONDON — Matthew Hedges, the British academic who was sentenced last week to life in prison by the United Arab Emirates on spying charges, was pardoned on Monday “with immediate effect,” the Emirati government announced, after British officials lobbied to have him released.

The conviction of Mr. Hedges, and the severity of the sentence, had been met with outrage in Britain, where Prime Minister Theresa May promised to raise the issue with the United Arab Emirates at the “highest level.”

Both the British government and Mr. Hedges’s wife, Daniela Tejada, have denied that he was a British spy. Family members have said that he was made to sign a confession written in Arabic, which they said he does not read or speak.

Mr. Hedges, 31, a graduate student at Durham University in England, was pardoned by Sheik Khalifa bin Zayed al-Nahyan, the emir of Abu Dhabi and president of the United Arab Emirates, the government said. A flight carrying him landed at London Heathrow Airport on Tuesday morning, Reuters reported.