The victory for openness campaigners will also have implications for Stormont's approach to disclosing public money claimed by politicians.

The Commons case involves the Additional Costs Allowance (ACA), which provides MPs with up to £23,000 a year for living expenses while in London.

It is used to claim mortgage interest payments and help fund second homes in the city.

Alternatively, the ACA can cover the cost of property rentals or hotel rooms.

Claims under a number of other categories are also permitted: food, service charges, utility bills, furnishings, maintenance, cleaning, insurance and security measures.

The Commons has been involved in a lengthy fight against freedom of information (FOI) requests for a detailed breakdown of ACA pay-outs.

Rulings by FOI authorities went against the House, leading it to appeal to the High Court in London.

The judges last week rejected its challenge, stating: "We have no doubt that the public interest is at stake.

"We are not here dealing with idle gossip, or public curiosity about what in truth are trivialities.

"The expenditure of public money through the payment of MPs' salaries and allowances is a matter of direct and reasonable interest to taxpayers."

MPs have now decided not to appeal this verdict. The FOI requests involved in the case relate to a sample of 14 members, including Prime Minister Gordon Brown and Tory leader David Cameron. Their ACA details are due to be released on Friday.

Breakdowns of claims made by all other MPs — including the 18 from Northern Ireland — will be published in the autumn, the Commons has stated.

This will be on a receipt-by-receipt and item-by-item basis and will cover a three-year period.

Full disclosure for all MPs is expected to involve around one million individual items.

The decision boosts the case for the Northern Ireland Assembly to provide much more detail on MLA allowances.

The ACA is one of the Commons expenses available to Sinn Fein MPs, despite the fact that they do not take their seats in Parliament.

Sinn Fein's five MPs claimed some £90,000 between them from the Commons for London living costs in the financial year 2006/07.

There has been controversy over the fact that husband and wife MPs are each entitled to claim the full ACA amount, while sharing the same accommodation

The DUP's Peter and Iris Robinson, who jointly own a flat in London's Docklands area, received a combined total of £39,944 from the Commons in 2006/07.

In 2006, Mr Robinson told this newspaper: "The London allowance is a matter which is dealt with by the authorities and has to meet the criteria that they set down. It's not a housing allowance, it's a London allowance."

According to Land Registry documentation, the MP couple purchased their Docklands property for £450,000 in 2001.