Peter Hobbs and John Mills, both 42, arrived at Heathrow airport on a flight from Sofia still maintaining their innocence over allegations that they were drug traffickers.
The two men, both of Enfield, north London, were sentenced to seven and a half years in jail after 20kg of heroin worth pounds 600,000 was found in their lorry in June 1995. They claimed the drugs were planted as they returned to Bulgaria from Turkey.
Human rights campaigners called their convictions "a gross miscarriage of justice" and fought for their release.
More than 20 members of Mr Hobbs's family greeted him at the airport, where he said it was brilliant to be back. "Without the letters and communication from my family it would have been virtually impossible to make it through," he said.
Mr Mills said he had been treated like an animal in prison, and it had been a "horrendous experience".
Stephen Jakobi, of the campaign group Fair Trials Abroad, who has been backing the men's case, greeted them at the airport. "These men have been put through a protracted four-year struggle," he said. "A lot of mistakes were made and not rectified. They will now go to the European Court of Human Rights and have their cases taken up there."Reuse content