Northern Ireland’s senior coroner acted unlawfully in deciding to suspend inquests into more than a dozen controversial killings, it was claimed yesterday.

Papers lodged at the High Court also state that cases adjourned by John Leckey over national security issues had already been considered by a senior legal adviser to the British government. Legal challenges to his decision will be heard on Monday.

New inquests were ordered by Northern Ireland Attorney General John Larkin QC in an attempt to discover more about the circumstances surrounding the deaths.

But 14 hearings have now been suspended after the coroner said Mr Larkin may have exceeded his powers.

The dispute centres on whether the attorney-general, appointed to the post of chief lawyer advising the Stormont Executive in 2010, has authority to initiate inquests dealing with matters of national security.

The coroner’s decision, announced on Thursday, provoked outrage among relatives of those whose deaths were to be scrutinised.

They include the family of 11-year-old Francis Rowntree, who was hit by a rubber bullet fired by a soldier in west Belfast in 1972.

Another case involves Gerard Slane, a 27-year-old father-of-three shot dead by the UFF at his home in the city in 1988.

His killing sparked claims of collusion between loyalist paramilitaries and the security forces.

Lawyers for both families are preparing legal challenges to the coroner’s ruling.

Proceedings have also been issued on behalf of relatives of Gerard Casey, who was murdered by the UFF in Rasharkin, Co Antrim in 1989.

Court papers claim that Mr Leckey’s decision should be quashed because it was reached in a procedurally unfair way and breaches human rights.

It is argued that the issues troubling the coroner do not apply to Mr Casey’s case because the former attorney-general for Northern Ireland, Baroness Scotland, considered it prior to the devolution of justice powers.

Following devolution she became advocate general and transferred the case to Mr Larkin.

Lawyers for the Slane family argue that she could only have done this if she was sure the case raised no potential national security issues.

“The said decision was unfair, unreasonable and unlawful,” the legal papers said.

Fearghal Shiels of Madden & Finucane Solicitors, who represent the next of kin in all three cases, said they were the first inquests directed by Mr Larkin after he assumed office in May 2010.

“However, each application was submitted almost three years before devolution and was therefore initially considered, in some detail, by the then attorney-general, Baroness Scotland QC,” he said.

“Following devolution, the only circumstances in which that transfer could have been permitted was where Baroness Scotland had been satisfied that there was no information, disclosure of which may have been against the interests of national security.”

Mr Shiels added that prior notice of the coroner’s intention to suspend the inquests could have allowed lawyers to persuade him his concerns were ill-conceived.

The solicitor said: “He has, in our view, acted unlawfully and we will seek to quash his decisions.”