The BBC's Liz MacKean: "Mr Mullen will consider whether to apply for compensation"

Nicholas Mullen was freed by the Court of Appeal in London after Lord Justice Rose, Mr Justice Colman and Mr Justice Maurice Kay said that the UK's "abuse of process" had to outweigh the conviction.

They said the facts of his involvement in a 1980s bombing campaign which left 14 dead and caused major damage were not considered in the appeal.

Supporters: Cheers as Mullen left court

Greeted by cheering supporters as he left the Court of Appeal, Mr Mullen said: "I'm relieved, I'm happy."

"I am glad to be going out of the front door rather than the back door today. I am just sorry it has taken so long."

He declined to outline his plans but did say he may consider seeking compensation from the UK government.

Mr Mullen, 50, was jailed for 30 years in June 1990 for his role in the IRA's "bomb factory" in Clapham, south west London - considered one of the major finds of arms outside of Northern Ireland.

The BBC's Liz MacKean: The judges took note of public revulsion at Mullen's crimes

Documents in the bomb factory led detectives to Mr Mullen but he fled to Zimbabwe with his girlfriend and daughter.

For Mr Mullen, Colin Mackay QC argued during the hearing that his client's conviction was unsafe because of the manner in which his client was returned to the UK had violated both Zimbabwean and international law.

He said that British secret services arranged the deportation and prevented Mr Mullen having access to lawyers before he was forcibly flown to Gatwick Airport, London.

He was also denied the right to be deported to a third country despite being an Irish citizen.

Freeing Mr Mullen, the judges said that they took note of the "public revulsion" at his involvement in the bombings.