Cameron: UK won't pay £1.7bn EU bill
"If people think I am paying that bill on 1 December, they have another think coming," the prime minister said in Brussels. "It is not going to happen."
But Commission President Jose Manuel Barroso said the demand should "not have come as a surprise" to the UK.
He said it was made under a system agreed by all the member states and based on data provided by them.
David Cameron has angrily insisted the UK will not pay £1.7bn being demanded by the European Union.
EU finance ministers have agreed to the UK's request for emergency talks about the top-up payment, which would add about a fifth to the UK's net EU contribution of £8.6bn for this year.
'Not acceptable' "It is an unacceptable way for this organisation to work - to suddenly present a bill like this for such a vast sum of money with so little time to pay it," he said.
Mr Cameron said he was "downright angry" and said the British public would find the "vast" sum "totally unacceptable".
"It is an unacceptable way to treat a country which is one of the biggest contributors to the EU."
