Three senior judges ruled yesterday that the Information Tribunal acted within its powers when it demanded that a detailed breakdown of MPs' additional costs allowances (ACA) must be provided under the Freedom of Information Act.

The President of the Queen's Bench Division, Sir Igor Judge, with Lord Justice Latham and Mr Justice Blake, also ruled that the addresses of MPs' second homes should be disclosed.

In what was hailed by information seekers as "a victory for democracy", they said full disclosure was necessary because the tribunal had concluded that the ACA system was "deeply flawed" and lacked accountability.

At stake was "public confidence in our system at its very pinnacle, the House of Commons itself", said the judges.

They said there was no evidence that revealing addresses would give rise to specific security risks, and exceptions could be made "in the most pressing cases" if that was to occur.

The judges granted a stay on their decision pending a possible urgent appeal to the Court of Appeal next week.

The Commons Members Estimate Committee, chaired by Speaker Michael Martin, which challenged the tribunal's decision, will consider its position next week.

MPs' expenses have come under sustained criticism in recent months following the publication of the "John Lewis list" of household items MPs can purchase under their £23,000-a-year second homes allowance.

The list includes £10,000 kitchens and £6,000 bathrooms.

The Information Tribunal ruled in February that the Commons authorities must provide a detailed breakdown of the ACAs of 14 named MPs, including party leaders Gordon Brown, and David Cameron and former Liberal Democrat leader Sir Menzies Campbell.

Nigel Giffin QC, appearing for the Commons, argued that the tribunal's decision, which requires breakdowns to include receipts and the addresses of properties bought, meant there would be "a substantial unlawful intrusion" into the lives of MPs and their families that could threaten their security at the hands of the "mad and bad".

Rejecting the QC's arguments, the judges said it was "highly significant" that none of the MPs subject to applications had suggested that they claimed allowances on the basis that detailed information would not be disclosed.

Yesterday's ruling against the Commons was a victory for journalists and information campaigners Heather Brooke, Ben Leapman and Jonathan Ungoed-Thomas.

They condemned the decision to appeal against the tribunal's decision, expected to cost more than £100,000, in order to preserve secrecy.

In court their QC Hugh Tomlinson referred to the case of an MP who claimed £100,000 for a property that did not exist and instances of MPs "juggling" their first and second homes in order to claim expenses.

There was also the issue of MPs letting out rooms in premises which they claimed were exclusively necessary for their Parliamentary duties.

Journalist Ms Brooke, author of citizens' guide Your Right to Know, has campaigned on the issue since 2006. She said after today's judgment: "This ruling will wrest control from the old boys' club and put it back where it belongs – with the constituents.

"All honest and hard-working MPs will welcome this opportunity to prove their openness to the electorate."

The assistant news editor of the Sunday Telegraph, Ben Leapman,said: "I am delighted by today's verdict.

"The Commons should not have spent three years fighting to keep these details secret, at huge cost to the public purse.

"Now MPs need to come up with a regular publication system which will reveal exactly what items they claim for."

The ruling was welcomed by pressure group the TaxPayers' Alliance, whose chief executive Matthew Elliott said: "This is a victory for taxpayers and democracy in Britain.

"People have a right to know what their elected representatives are doing and taxpayers deserve to know how their money is being spent. This verdict will boost transparency and bring Parliament closer to the people.

"It's a shame that the Speaker has wasted so much of our money trying to keep this information secret. When he should have been improving the standing of Parliament, he has instead brought it into even greater disrepute by his contempt for the public."

Gordon Brown's spokesman told reporters at a regular daily briefing: "The Prime Minister has made clear that he is relaxed about the publication of his expense details, but this is a matter for the House authorities."