United Left TD Joan Collins has been awarded 75% of her legal costs in her unsuccessful challenge to the promissory notes issued by the Minister for Finance in favour of Anglo Irish Bank and the Educational Building Society.
The decision means the State must pay most of the costs of the case.
The three-judge divisional High Court ruled that it was an exceptional case which merited a departure from the normal rule regarding costs.
Normally, the losing party must pay the costs of the case.
The court ruled that Ms Collins was not entitled to her full costs but given the exceptional nature of the litigation, it awarded her 75%.
It said it noted the importance of the novel question of constitutional law raised by Ms Collins and the weighty issues raised by this litigation.
It also noted the importance to the State and its citizens that the constitutionality of the important and novel executive and legislative decisions far reaching consequences be judicially determined.
It also noted that Ms Collins was a public representative and did not act for personal advantage.
And it also noted that the decision clarified and provided certainty for the State in the operation of its financial procedures.
The State had urged the court to award costs against Ms Collins as she was appealing the decision.
It had argued that the issues raised were important but that did not mean it was in the public interest to take the case.
Ms Collins' lawyers had argued that the case went to the core of the Constitution and concerned whether or not it was lawful for the minister and the Government to make massive dispersals of public monies without Dáil approval.
The court ruled that Ms Collins' case raised an issue which had never previously been considered by the High Court.
It said it was in the public interest that this point should be determined.
It ruled that it was in the public interest that the constitutionality of the far reaching legislation which permitted the promissory notes to be issued should be determined.
It found that the question of whether or not Ms Collins was appealing the High Court judgment was "an entirely neutral factor" when it came to deciding costs.