The Government said today it was lifting the "veil of secrecy" over public spending - while acknowledging that most people would be left none the wiser as a result.
The Treasury released the Combined On-line Information System - known as Coins - which gives a detailed breakdown of public spending decisions over the past five years.
It is one of a raft of Whitehall databases David Cameron has ordered to be made public as part of the new coalition Government's commitment to greater openness.
The Treasury press notice hailed it as "the most detailed UK public expenditure data ever released", covering millions of individual lines of public sector expenditure.
However it also suggested it would be of more interest to "institutions and experts" than the ordinary public as the material was "complex" and was being released "in its raw form, requiring technical expertise to process".
Treasury Chief Secretary Danny Alexander insisted the release was a "major step forward" - although he promised future releases would be more accessible to the general public.
"For too long the previous government acted as if the public had no right to know where their hard earned taxes were spent. Today we have lifted that veil of secrecy by releasing detailed spending figures dating back to 2008," he said.
"This data is complex, but this is major step forward and shows we are delivering on our promise to make this Government more open and transparent while ensuring we deliver value for money for the taxpayer.
"I hope people will take the opportunity to scrutinise carefully how their money is being spent - as I am doing every day in preparation for the spending review."
The release was welcomed as a "fantastic victory for openness" by the TaxPayers' Alliance campaign group.
"It is right that this data is out in the public domain, saving departments time and money responding to Freedom of Information requests," said TPA chief executive Matthew Elliot.
"There is an army of enthusiastic, skilled amateurs out there who will gladly explore and use this information to suggest ways in which the Government can save money and improve public services."
Chancellor George Osborne complained last year that Gordon Brown had intervened to deny his call for the figures to be published to help him formulate opposition policy.
The claim was strongly denied by Labour, which said the decision was taken by the Civil Service, but Mr Osborne promised to release the data if he took over at the Treasury.
Earlier this week, the names, pay and perks of the 172 senior civil servants earning more than £150,000 were released in the first part of the disclosure programme.
It was also announced that people will be able to check the weekly MRSA and Clostridium difficile (C diff) rates at their local hospital.
Government contracts over £10,000 will be published on a single website from September with items of central Government spending over £25,000 and local government over £500 shortly afterwards.Reuse content