Mr Paisley said he would protect his source and go to jail rather than name him
The High Court has ordered Ian Paisley Jnr to identify the prison officer who told him about files which were destroyed by the NI Prison Service.
The inquiry into the murder of LVF leader Billy Wright had issued the challenge after Mr Paisley refused to reveal the identity of the officer.
Mr Paisley said the officer told him documents were destroyed after the loyalist's murder in 1997.
He said he would protect his source and go to jail rather than name him.
"I cannot and will not give the name of this individual. I will not break my word," he said.
"The name of the source will not be revealed by me, will never be revealed by me.
"If it's that ominous choice, the choice is obvious. If the courts were to say to me, 'Mr Paisley either name or go to jail' - the choice is jail."
In June 2007, Mr Paisley wrote to Billy Wright's father with information that the NI Prison Service had employed people to destroy about 5,600 files shortly after his son was shot at the Maze Prison in December 1997.
Billy Wright was shot dead in the Maze prison in 1997
Mr Paisley had said he was told of an alleged policy within the prison service to destroy a large number of files as an emergency due to data protection legislation.
He said this information, which was provided by a "senior prison officer", claimed that the decision to destroy the files was "taken at the top".
In his ruling, Mr Justice Gillen said that although it was important for elected representatives to be able to protect the confidentiality of a source, the information played a central part in enabling the inquiry to determine whether or not the prison authorities had facilitated Mr Wright's death.
"I consider than an order made by me to enforce the matter certified is measured and justified when set against the weight of the freedom of expression which must be accorded to public representatives," he added.
He said that he was satisfied that the inquiry had provided a clear and compelling case and ordered Mr Paisley to provide the information within 17 days.
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