Britain, France, Germany, Finland and the Netherlands called on Saturday for the EU budget to be frozen until at least 2020, in a joint letter to the European Commission.

The letter, addressed to European Commission President Jose Manuel Barroso, said that the European Union's joint budget should not grow faster than the rate of inflation in the bloc's post-2013 long-term budget.

European public spending cannot be exempted from member states' considerable efforts to get their public spending under control, the letter, which was released by the French presidency, said.

The EU's 27 countries will start talks in mid-2011 on the long-term budget, which runs from 2014 until 2020 or longer.

Next year's budget is worth 126.5 billion euros ($166.8 billion), with more than 40 percent of it going on agriculture and a third on aid to poor regions.

The joint letter was signed by French President Nicolas Sarkozy, German Chancellor Angela Merkel, British Prime Minister David Cameron, Dutch Prime Minister Mark Rutte and Finnish Prime Minister Mari Kiviniemi.

Cameron used an EU summit in Brussels on Friday to drum up support for a leaner budget, telling reporters that the bloc needed real budgetary restraint.

However, efforts to agree a tighter budget are likely to run up against stiff opposition from poorer eastern European countries that currently benefit most from EU largesse and Poland's Prime Minister Donald Tusk said his country would resist cuts.

(Reporting by Leigh Thomas; Editing by John Stonestreet)