Former Sinn Féin deputy president and MP Pat Doherty sanctioned the 1983 killing of prison officer Brian Stack in Dublin, the dead man’s son Austin alleged in the high court in London.

The allegation was made during a civil suit taken against former Sinn Féin leader, Gerry Adams for £1 in damages by three victims of IRA bombings in England, who argue that he was “directly responsible” for three IRA bombings between 1973 and 1996.

Brian Stack was the chief prison officer at Portlaoise Prison and died in September 1984 – 18 months after he was shot in the head by members of the Provisional IRA outside a boxing competition in Dublin.

“Pat Doherty sanctioned the murder of my father,” Austin Stack told Justice Jonathan Swift.

He said he believed that Doherty, an MP for West Tyrone for almost two decades, had then been quartermaster general of the IRA.

On Thursday, Austin Stack accused Adams of repeatedly telling lies about a meeting they had in 2013 where Stack sought the then Sinn Féin leader’s help to find out more about his father’s killing.

Adams had given false information about the encounter, he claimed, telling An Garda Siochána that Stack had given four names of people involved in his father’s killing when Stack said he had done no such thing.

Stack said he had been given information about the killing from two respected journalists with long-standing knowledge of the IRA: former Garda chief supt Peter Maguire and IRA informer Sean O’Callaghan.

Adams, he said, later ordered his close colleague Martin “Duckster” Lynch to investigate his father’s killing, he said, which is only something one would do if one were part of the supervisory arm of an organisation.

Later, Lynch told him the matter had been investigated and found that the killing had not been sanctioned and the person responsible had “been disciplined”.

Adams was a senior figure in the IRA, Stack argued, had “an intimate knowledge” of its workings and “was able to speak with one voice on behalf of the IRA and its former volunteers” when he apologised in the Dáil for Det Gda Jerry McCabe’s killing.