Exeter academic Matthew Hedges has arrived back in the UK from the United Arab Emirates, where he was jailed for life for spying then given a pardon by the nation's president days later.
A family spokesman confirmed that Mr Hedges has arrived at Heathrow Airport.
The PhD student has thanked everyone involved in "securing my release".
Matthew Hedges was freed on Monday after a high-profile battle with the Gulf state ally, but officials persisted in calling him an MI6 spy - a claim denied by family and colleagues.
UAE minister of state for foreign affairs Anwar Gargash said the pardon would allow the two countries to "return our focus to the underlying fundamental strength of the UAE-UK bilateral relationship", the WAM Emirates news agency reported. Professor Stuart Corbridge, vice-chancellor of Durham University, said staff were "absolutely delighted" to learn of the news.