The big surprise in his "radical reform" Budget on Tuesday will be a multi-million-pound fund to end admission charges at great national institutions such as the Science Museum and the Victoria and Albert Museum.
The Government's decision, which follows a strongly fought campaign by the Independent on Sunday and The Independent to keep access to art and history free, ends months of uncertainty when Labour appeared to be on the brink of ditching its pre-election opposition to charges.
Arts experts calculate that it will cost around pounds 40m a year to restore free admission to the V & A, the Imperial War, National Maritime and Science museums, which imposed charges because of funding cuts.
It could cost as much again to ensure that access to the National Gallery, the Tate, the National Portrait Gallery and the British Museum remains free.
But, faced with mounting public hostility to the introduction of compulsory charges, and evidence of sharp falls in visitor numbers virtually everywhere they have been imposed, the Chancellor has decided to extend the support he gave in his first Budget to the film industry to the wider arts world.
His "Budget for the Arts" is expected to make provision to meet the cost of maintaining the museums, either through a straight increase in the annual grant they already receive or through money from the National Lottery, or a combination of the two.
Mr Brown will argue that the Government has a responsibility to ensure that great national institutions such as the Tate are open to all, regardless of circumstances.
Before the election last May Tony Blair said: "We are concerned about the introduction of admission charges in national museums. The evidence suggests that high charges can lead to a big decline in attendance." In June, arts minister Mark Fisher reiterated the policy, insisting: "We do not want anybody to be charged entrance fees."
But Labour subsequently ordered a review of the policy, amid fears that it would be downgraded to an "aspiration" that might be achieved during the lifetime of the first parliament. Anxious museum directors, faced with funding cuts, began to plan for admission charges.
At the Tate Gallery, which has been free for 100 years since it was set up by Victorian philanthropist Henry Tate, the director Nick Serota said the three million visitors a year would have to pay to get in from next month because the gallery had run up a pounds 1m deficit. The trustees of the British Museum, meanwhile, have drawn up plans to charge its six million visitors pounds 5, breaking with a 250-year history of free admission.
But the almost-universal experience of charges is that the public stay away in droves. In 1987/88, the last year before charges were introduced, the Science Museum had 3,166,000 visitors. That figure immediately fell to 1.1 million, and had only recovered to 1,548,000 in 1996/97.
At the Natural History Museum, it was a similar story. Before charges, 2.5 million visitors; after, 1.8 million. The National Maritime Museum was even harder hit, down from 799,000 to 468,000, and the Royal Air Force Museum tumbled from 323,000 visitors to 135,000. The Victoria and Albert Museum saw the number of people passing through its doors fall from 1,578,000 to 1.2 million.
The only museum to increase visitor numbers after bringing in compulsory charges is the Imperial War Museum, up from 396,000 to 444,000 last year, though much of the rise is attributable to a series of war anniversaries and a highly successful range of exhibitions such as the story of wartime evacuees.
Arts campaign, page 22