The sister of the Guildford Four's Gerry Conlon has asked for the 1974 pub bombings inquests to be resumed, according to lawyers.
Mr Conlon was one of the quartet wrongly imprisoned for the IRA attacks in the Surrey town which killed five people - four soldiers and a civilian - and injured 65.
The Guildford Four were handed life sentences, but had their convictions overturned in 1989, and their case became one of the best known miscarriages of justice in British legal history.
Belfast-based firm KRW Law said it has applied to the senior coroner for Surrey to resume the inquests on behalf of Mr Conlon's sister Ann McKernan and a soldier who survived and who wishes to remain anonymous.
The firm said the application was on the basis that the inquests were never completed following the conviction of the Guildford Four.
Soldiers Caroline Slater (18), William Forsyth (18), John Hunter (17) and Ann Hamilton (19) and civilian Paul Craig (22) died in the blast at the Horse and Groom pub on October 5 1974.
KRW Law believes the resumption of the inquests would serve the interests of the victims and the wider public interest, adding that its clients still have unanswered questions.
The lawyers said their clients want to know why there was no subsequent police investigation following the release of the Guildford Four and why questions remain over the original prosecution.
The firm said that for its clients these inquests would be "an exercise in their right to truth, justice and accountability".
Last month, the lawyers applied to the Attorney General for England and Wales for him to consider ordering a new police investigation into the bombings, specifically regarding the original investigation by Surrey Police, the original prosecution of the Guildford Four and the subsequent inconclusive findings of judicial inquiry.
Kevin Winters, a partner at the firm, said its experience of assisting victims and relatives from the conflict in Northern Ireland has shown that participation in a fresh or resumed inquest can provide "an important venue for truth seeking and resolution".
He added: "The victims of the Birmingham and Guildford bombings - and those communities - are entitled as a matter of law, and indeed internationally binding legal agreement, to have access to a judicially supervised forum which provides unambiguous access to truth recovery."
Mr Conlon died in June 2014, three weeks after he was diagnosed with lung cancer.
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