The Sinn Féin president, Gerry Adams, has launched a legal attempt to overturn two convictions connected to a planned IRA jail break at the height of the Troubles in Northern Ireland.

Adams’s lawyers argued at the court of appeal in Belfast on Tuesday that the 1975 convictions for earlier escape attempts from the Maze prison, then known as Long Kesh, should be quashed.

The legal team representing Adams, who was not in court, claimed that because he was in prison because of the practice of internment without trial, his detention was unlawful.

Sean Doran QC, who is representing the former West Belfast MP, told the three judges: “Each conviction is for attempting to escape from lawful custody.”

Doran said that in Adams’ case there was no “personal consideration” of the merits of his detention.

He said the appeal was related to Christmas Eve 1973, when the state alleged that four republican prisoners, including Adams, had cut a hole in the prison fence and were intercepted before fleeing from the jail.

The second conviction concerned a 1974 plot by the IRA to kidnap a man who resembled Adams, dye his hair, put a false beard on him and then substitute him for Adams inside the prison.

Adams was among hundreds of men interned without trial in 1972 during a highly controversial security crackdown by the British government.

A year later, he was released from Long Kesh by the British government to attend talks with the then Northern Ireland secretary, William Whitelaw, in London. Those discussions in London broke down and led to an escalation of IRA violence that summer.

In 1973, Adams was re-arrested in West Belfast and reinterned.

Internment without trial was heavily criticised across the world, but did not end until 1975. By then nearly 2,000 people had been detained without trial, the vast majority of them republicans and politically uninvolved civilians from the Catholic community.

A number of former internees, known as the Hooded Men, have taken a high-profile legal case against the British state, seeking compensation for alleged torture by army and police officers during their detention.