On Tuesday, the Department for Culture, Media and Sport announced that the art gallery on London's Southbank is to receive an injection of £5m in the coming financial year, with year-on-year increases of £6m thereafter, to ensure free admission. But the Conservative Party has accused the government of plundering funds earmarked to help provide free access to national museums across the country.
"I've had my doubts about how committed the government has really been to introducing universal free admission for some time," Conservative arts spokesman Peter Ainsworth told the BBC.
Admission promise "It seems that if £6m is being siphoned off to be put into this particular project, that must call into question even more a commitment that shouldn't have been given in the first place."
Although free access was not a specific manifesto pledge, the Labour party has long talked about the possibility of free access to museums and art galleries.
In July 1998, the government outlined its vision for UK museums in the millennium by announcing details of £290m of extra funding for arts, museums and galleries.
The money was intended to go towards helping major national museums to establish a universal entry fee by the year 2001, while children should get free entry by 1999 and pensioners by 2000.
A year later, the government made a promise of free admission to all in 2001, and £30m was extracted from the Treasury so charging could end in a number of London museums and others that are free could remain so.
'Widening access'
But the culture ministry told the BBC that they are still actively looking at providing free access, but there was no point in categorically saying that all museums that charge will become free, because it was up to the museum trustees.
"What we said when we announced the changes a year-and-a-half ago was that we were going to widen access still further. There is extra money to do that and discussions are underway with the museums and directors," culture minister Chris Smith told the BBC on Tuesday.
He did not make it clear whether "widening access" was the same as free access to all.
National museums are currently split between those which charge most visitors - the Science Museum, Natural History Museum, Victoria and Albert and Imperial War Museum, for instance - and those which are free.
These are the National Gallery, National Portrait Gallery, Tate Gallery and the British Museum
The government's policy of free access for children has, so far, resulted in attendances up by more than 20% in six months, with some museums reporting a 70% rise.
'Political will'
But David Barrie, director of the National Art Collection, who has campaigned for free access, told the BBC that did not believe the policy was on the Treasury's agenda.
"What we really need is political will at the highest level," said Mr Barrie.
"We want the Treasury to link arms with Chris Smith and join in making possible something that is of the greatest importance - free access."
In what could be an embarrassment to the government, it has emerged that some museums actually like charging for admission.
The Natural History Museum, for one, maintains that it has been able to run a successful and attractive museum because of its charging policy.
"The last thing I want to happen for this museum is that our ability to charge is reduced but the compensation we get from the government is not enough to make good."