A lawyer for the woman who successfully challenged the appointment told three appeal judges that Mrs McDougall's selection amounted to "an abuse of power".

Barry MacDonald QC attacked former Secretary of State Peter Hain for failing to explain why he picked the DUP nominee for the unadvertised, interim job.

"The fact is that the appointment of Mrs McDougall was an exercise in pork barrel politics that was carried out in a manner that would have drawn admiring glances in Tammany Hall," Mr MacDonald said.

He launched the attack during the second day of the Northern Ireland Office's appeal against last year's High Court ruling that Mrs McDougall's 2005 appointment was an illegal political favour to the DUP.

Mrs McDougall - who was unaware of the NIO's selection procedure - was the only candidate interviewed for the post after her name was put forward by Ian Paisley.

The appeal case was being heard a matter days before Mr Paisley, now First Minister, and Deputy First Martin McGuinness are due to announce the appointment of a permanent Victims Commissioner.

Representing West Belfast woman Brenda Downes, Mr MacDonald told Lord Chief Justice Sir Brian Kerr, Lord Justice Higgins and Mr Justice Morgan that they need to "know exactly why Mrs McDougall was appointed. "The Secretary of State is still not prepared to admit that the decision to appoint Mrs McDougall was actually made by the DUP, not by him," he said.

The QC said the Government made the "quite outlandish claim" that the original High Court judge was wrong to believe Mr Hain was bound by principles of fairness and openness when he appointed Mrs McDougall.

"The Secretary of State's case is that the court was wrong to believe the Government has wedded itself to merit, scrutiny, openness and transparency," he said.

"It captures the essence of this appeal because the court is being invited to disregard the abuse of power."

Mr MacDonald said the NIO has had several opportunities to file statements from Mr Hain "explaining why he made the appointment."

He said it was obvious that the "continuing reluctance on the part of the Secretary of State to explain what happened and admit why he did what he did".

The appeal judges are not expected to deliver a ruling in the case until the New Year.