DUP MLA Ian Paisley Jnr could be jailed if he refuses to comply with a High Court order to reveal the identity of a prison officer who told him about an alleged file destruction policy, a judge has said.

Mr Justice Gillen set out the potential consequences as he ruled that legal proceedings brought by the inquiry into loyalist leader Billy Wright’s murder were civil, rather than criminal.

Lawyers for the tribunal chaired by Lord MacLean have gone to court in an attempt to compel Mr Paisley to co-operate with its requests for the officer’s name. The North Antrim MLA has so far insisted he will not identify the man who supplied the information, which he then passed to David Wright, father of the assassinated LVF chief.

Mr Paisley said he was told of an alleged policy in the Prison Service to destroy a large number of files as an emergency due to data protection legislation. It was suggested that up to 5,600 files were destroyed shortly after Wright (37), was shot dead by republicans in the Maze Jail in December 1997.

Mr Paisley said details were given to him in confidence by a senior prison officer who approached him last June while he was a Junior Minister at Stormont. With the information regarded as relevant to the public inquiry into claims of security force collusion in the killing, he decided the most appropriate action was to pass it on to David Wright.

The High Court application, brought under Section 36 of the Inquiries Act which deals with enforcement issues, is believed to be the first of its kind to be made in the UK.

The judge said if any enforcement steps were taken and failed to secure compliance, the “dual nature of civil contempt will come into play”.

He said: “At that stage the High Court will have a substantial interest in seeing that any order it makes must be upheld — if necessary by committal to prison for contempt.”