Britain is facing a shock demand for an extra £1.7 billion towards the European Union budget.
The European Commission says the UK owes the extra money because our economy has performed better than expected in recent decades.
It is due for payment on December 1 – just days after the crunch Rochester & Strood by-election at which David Cameron’s Tories are struggling to fight off a challenge from anti-EU Ukip.
Ammunition: The announcement will play into the hands of UKIP leader Nigel Farage
Mr Cameron held talks with Dutch counterpart Mark Rutte, who is also facing a large demand for more cash, on how they can challenge the surcharges.
The surprise development is set to overshadow the European Council summit in Brussels, where Mr Cameron is meeting leaders of the 27 other EU States, some of which are looking forward to reductions in their contributions.
Preliminary figures seen by the Financial Times suggest that Britain is facing by far the biggest top-up, while the Netherlands is being asked for an extra 642 million euro.
By contrast, Germany receives a rebate of 779m euro, France 1bn and Poland 316m.
The extra money would add almost a fifth to the UK’s annual contribution to the EU budget of £8.6 billion.
A Downing Street source made clear the UK will challenge the demand.
“It’s not acceptable to just change the fees for previous years and demand them back at a moment’s notice,” said the source.
Fightback: Prime Minister David Cameron will challenge the demand for more money
“The European Commission was not expecting this money and does not need this money and we will work with other countries similarly affected to do all we can to challenge this.”
The surcharge is affected by changes in the way the EU calculated gross national income, which now includes elements such as prostitution and illegal drugs, said the FT.
But a Commission spokesman aid it was principally due to changes in the relative economic strength of the EU’s member states.
“Britain’s contribution reflects an increase in wealth, just as in Britain you pay more to the Inland Revenue if your earnings go up,” said Patrizio Fiorilli, a Commission spokesperson.
The commission’s demand for additional funding from Britain was strongly demanded by the leader of the Conservative MEPs, Syed Kamall.
“The European Commission is penalising Britain for taking tough decisions, putting in place a long term economic plan and for having the most successful economy in the EU while actually rewarding France for being an economic basket case,” he said.
“David Cameron is absolutely right to stand up to this attempted daylight robbery by the EU.”
“This is outrageous and harms the EU’s relationship with Britain. At times like this, the European Commission can be its own worst enemy.”