More than 2,000 museums and galleries across the UK have joined forces to produce A Manifesto for Museums - asking the government for an extra £115m per year to maintain some services and extend others.
How important are museums to Britain?
UK museums get 100 million visits per year, the manifesto says
The manifesto says these institutions are hugely important in many different ways - helping education, tourism, local communities, creativity, research and the economy as a whole.
Museums generate £3bn for the economy and employ 40,000 people, it says. And members of the public make 100 million museum visits per year - more than the total crowds at all the UK's live sporting events put together.
But they are not as important as things like schools, are they?
Some say they are. Sir Nicholas Serota, director of the Tate, says they are "part of the fabric of society" like schools and libraries - and should be treated as such. Half of all school-age children visit museums at least once a year, and the manifesto says 85% of parents think museum visits should be on the national curriculum.
Why do the museums need this money?
They say museums have been hard-done-by in recent years - and have slipped down the list of government priorities.
Many complain that government grants have not kept up with inflation and the Treasury has failed to compensate them adequately for getting rid of admission fees.
Where would the £115m go?
Museums and galleries may not be able to buy as many new objects
About 30 national museums want an extra £50m per year. These include the famous London institutions like the Tate and the Natural History Museum, the other national museums in England, Scotland, Wales and Northern Ireland, the three national libraries and the National Archives.
Local museums across the UK - through the Museums, Archives and Libraries Council - are asking for another £35m per year. Projects where the national and regional museums work together need £15m and the final £15m would be used to buy new objects for collections.
What would it be used for?
Fixing leaky roofs, better storage conditions, keeping exhibitions open, improving access for schools, putting collections online - the institutions have a long list of things to spend their money on.
The national museums put the most urgent case, saying they may not be able to sustain their current levels of service and access without more money. They also say there is £150m of building and maintenance work waiting to be done.
Will museums actually get this money?
Highly unlikely - at least, not all of it. The museums must keep pressure on the government to make sure they are not forgotten, but the truth is that they are far from the top of the list when it comes to handing out taxpayers' money.
Chancellor Gordon Brown will have to weigh up the nation's priorities in his comprehensive spending review in June - which will set out how much each government department will have to spend. Core public services such as schools and hospitals are seen as more in need.
What will happen if they do not get this money?
This manifesto is a wish list, and the country's museums will by no means collapse if they do not get this money.
But some attractions may not be able to afford to keep all exhibitions open, some free museums may introduce admission fees, education and community programmes could be scrapped, there will be less money to buy new objects and existing collections may not be kept in the best conditions.