Mr Paisley claims the NI Prison Service destroyed files
Ian Paisley Jnr has said he will not comply with a High Court deadline for him to reveal the source of information relating to the murder of Billy Wright.
Mr Paisley claims a former prison warder gave him vital information about procedures at the Maze prison where the LVF leader was shot dead in 1997.
He said it was now "up to the courts" to decide whether punishing him was "in the public interest".
Today is the deadline for him to reveal his source to the Billy Wright inquiry.
Mr Paisley said: "I'm not going to appeal today - I don't believe it's in my personal or financial interests to keep it running."
"If I appeal and win, this case goes to the House of Lords," he said.
"If I don't appeal and just let the case continue to run back to the High Court, nothing changes for me - I'm not revealing the name."
Mr Paisley said there was an important principle at stake.
He said: "Do I have the same rights as priests, solicitors or journalists to protect my source or should I so damage the confidence of the public that they can no longer go to a public representative in confidence?
"This is about protecting the rights of constituents - ultimately we are their servants and I have to put them first. I will be taking this name to my grave."
Mr Paisley had previously insisted he was prepared to go to jail to protect his source, but legal commentator Joshua Rosenberg said a fine was a more likely punishment.
"There's no obligation on courts to send people to prison for contempt - that obviously is the most serious punishment," he said.
"I suppose the question is, would Mr Paisley pay the fine?"
Mr Paisley said: "I don't believe I would."
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.
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 in March, 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.
A spokesman for the Billy Wright Inquiry said on Monday they were aware of Mr Paisley's decision and were considering their position.