A Stormont Assembly member who defied a judge's ruling ordering him to reveal a confidential source should not be sent to jail because that's exactly what he wants, a court heard today.

Ian Paisley jnr would relish a term behind bars because he appears to think it would further his political career, a lawyer pursuing the information told Belfast High Court.

Stating the reasons why he was not seeking a custodial sentence, QC John Larkin said: "Mr Paisley appears to want it too much."

To emphasise his point, the barrister then made humorous reference to Formula One supremo Max Mosley's indulgences in sexual bondage sessions.

"Brandishing custody before Mr Paisley appears to be like brandishing a whip before Max Mosley," he said, to laughs from around the court.

The North Antrim representative, who was accompanied at the hearing by his father and former Northern Ireland First Minister Dr Ian Paisley, has refused to disclose the name of a prison officer to the inquiry team that's probing the murder of loyalist paramilitary leader Billy Wright inside the Maze prison in 1997.

The officer, a constituent of the MLA, told him that there was a policy of file destruction within the Prison Service in the wake of the killing by INLA inmates.

The inquiry team took a case against Mr Paisley demanding that he name the name, but despite the court finding against him he has so far refused to pass it over, claiming it would break a pledge of confidentiality.

Mr Larkin showed judge Mr Justice Gillen an interview Mr Paisley had given to a Sunday newspaper saying going to jail had not done his father's political career any harm, and it wouldn't do his any either.

He said this was evidence that the MLA wanted to go to prison.

Mr Paisley's lawyer Joseph Aiken denied that his client wanted to go to jail.

He said he was facing a mounting bill - that currently stands at £35,000 - for defending the principle of confidentiality in the courts, and that that should be punishment enough.

The father of four has already claimed he has been forced to put his house on the market to foot the bill and today his lawyer told Justice Gillen that his client was not well off.

"He comes from a famous and high profile family in Northern Ireland but perhaps contrary to public perception he has a modest financial position given his public prominence and roles he carries out," he said.

He also revealed that Mr Paisley had made two attempts to convince his source to allow him to disclose his identity but that the officer had refused.

Mr Aiken also questioned the reasons why the case against Mr Paisley had been mounted given information about the file destruction policy had already be heard by the inquiry from prison officers actually involved in it.

He noted that other high profile inquiries had been faced with witnesses who had declined to reveal the identities of others - most notably current Stormont Deputy First Minister and former IRA member Martin McGuinness during the Bloody Sunday probe - but had not taken them to court.

Justice Gillen acknowledged that other witnesses had given evidence about the file destruction policy but pointed out that Mr Paisley's informant appeared to be suggesting that there were "dark or even criminal" motivations behind the practice.

"That's precisely why the inquiry wants to speak to this man," he said.

Mr Larkin, who is set to become Northern Ireland's attorney general, said the inquiry was not seeking either a prison sentence or a day by day fine.

As well as Mr Paisley's alleged desire for one, he said the cost to the taxpayer and the potential ineffectiveness of a jail term were other reasons why he was not pursuing one.

The QC said as the inquiry was still seeking the information, any fine should have a coercive element in attempting to force the respondent to comply with the court.

Earlier Justice Gillen said while Mr Paisley had clearly defied the court order, he had to be proportionate in whatever punishment he imposed.

"However imprudent and rash the respondent, making great public statements and painting himself into a corner, the court has to be proportionate in how it acts," he said.

He told the court he intends to give his ruling tomorrow.