"If we tried to call it off at this stage we'd be lynched," said Alan Leighton, museums officer at the union Prospect, whose members voted 85% in favour of a series of one-day strikes.
"It's a disaster," said David Barrie, director of the independent arts charity the Art Fund, which led the campaign for free museums - which is partly blamed for the British Museum's financial plight, as extra government funding went to compensate only the museums which scrapped admission charges. "I believe it will do irreparable damage to the museum's relations with the public, with the government, and to its own internal structure. I think it's a catastrophe."
He said the strike, against a rescue programme which includes job cuts of 15%, was a shout of rage from the staff: "They are boilingly angry."
Gareth Williams, chairman of the trades union group in the museum and curator of early medieval coins, said his colleagues were resolute: "There is of course deep regret and anxiety that what is proposed will impact on the public. But we feel passionately that it is better to inconvenience however many thousands turn up at the museum on one day, in order to protect the future of the museum for generations of visitors to come.
Underfunding
"And we are in the worst plight, but this is not uniquely a British Museum problem - there are others among the nationals, notably the Tate and the National Gallery, which are heading in the same direction. We must take the only means we can, to alert the public to the devastating cumulative effect of systematic government underfunding."
The First Division, which represents the top tier of staff, has chosen not to ballot, but most of its members are taking annual leave rather than pass the pickets.
There was a sharp intake of breath from senior management last week - and a gasp of astonishment from the staff - when the museum director, Robert Anderson, said he did not condone the strike but understood why staff were striking.
How did it come to this? The British Museum is in the superleague of world museums, its collections and its curatorial expertise unrivalled. The spectacular Great Court, Lord Foster's creation of a vast glass domed clearing in a space formerly stuffed with Victorian books, was one of the most admired millennium projects. It gets 4.6 million visitors a year, more than Tate Modern. A year of parties and fireworks was planned for next year's 250th anniversary.
But the museum is also a business tottering under the weight of a deficit, estimated to hit £6.5m within 18 months. The Great Court, heralded by Lord Foster as a bustling new piazza which would transform the museum's atmosphere, is only open until late-ish three nights a week - and on those stands eerily deserted, as bustling as an embalming parlour.
The combination of the foot and mouth and September 11 disasters last year meant that the new shops and cafes never reached their earnings targets, and corporate entertainment, for which the site was expected to be a magnet, collapsed.
The rescue programme, accepted by the trustees, will only stop the rot: the museum calculates it needs an extra £6m a year from the government to stop the slide back into debt.
The line offered by both management and the striking unions is that year-on-year cuts or underfunding by the government have eroded the grant in real terms by up to 30% over 15 years.
Outside observers believe the reasons for the crisis are more complex. Tim Schadla Hall, an expert on museum management at University College London and former head of Leicestershire museums, lays the blame squarely on senior management and the panel of 25 trustees, under the guidance of outgoing chairman Grahame Greene: "Any outside objective analysis would suggest that the need to make cuts of 15% in the budget could have been foreseen at least a year ago, and probably for far longer. The cumulative deficit must have been visible before 1999-2000.
"Therefore, whatever claims are made that the government has underfunded the museum, it is still clear that the senior management of the museum and or the trustees must have been aware of the problem a long time ago and must bear heavy responsibility for its present plight."
Another observer, with excellent contacts among the trustees and the government, says the government has effectively washed its hands of the museum, having put in Susanna Taverne, a City moderniser, as chief executive to knock some modern management sense into Bloomsbury - only to see her retire from the fray within two years.
Contempt
"The truth is that the trustees and the keepers have treated outsiders, including government ministers and senior officials, with lofty contempt," the observer said. "The attitude has been 'here's some poxy little civil servant who couldn't tell a Roman coin from a Greek'. Now that might well be true, but if you get almost all your funding from the British government, the last thing you should do is to piss them off completely."
The same observer is gravely anxious for Neil McGregor, the widely liked and admired director of the National Gallery who takes over the British Museum on August 1. "McGregor is parachuting into the Battle of the Bulge. This one would be a tough challenge for a Rupert Murdoch, and McGregor ain't no Rupert Murdoch."
The strike is a wretched welcome mat for Mr McGregor, and for the less publicised appointment of Dawn Austwick, former project director at Tate Modern, as director of resources, to take charge of finance, information systems, staff and building management, with an annual budget of £25m.
Staff bitterness is such that one senior member refused to invite Robert Anderson, the director, to his retirement party. It is partly because they are now facing the third round of cuts in five years: 40 were lost after a withering financial study in 1997, dozens more under the grue somely tagged "Opportunities 2,000" project - both announced as measures to put the museum on an even keel.
The Guardian has seen the detailed prescription of where the cuts should now fall, from carpenters to curators. Savings already announced include closing galleries for part of the time, charging for access to stores, and ruthless disposal of property.
Further savings will now be made by amalgamating departments, including a new super department bundling together 5,000 years of collections from prehistoric to medieval: "Everything from stone hand axes to clocks under one keeper - it's ludicrous!" snorted Andrew Selkirk, editor of Current Archaeology.
For those departments, and Gareth Williams' coins and medals department - which, as he points out, handles thousands of queries every year from regional museums and members of the public - the report says bluntly: "Volunteers coming from coins and medals, ethnography and M&ME [medieval and modern Europe] will be particularly encouraged."
Mr Schadla Hall says the outlook is bleak: "The tragedy is that those who are going to suffer these cuts are not those responsible, but the bulk of the staff who work in the museum and have no control whatsoever over the financial position of the museum and its management."
A security officer who voted for the strike views the future with utter pessimism: "We're never told anything, we're not consulted, and the work we do is not respected. I don't think that is going to change."
