David Cameron has insisted the proposed rise in European Union spending was "quite wrong" as he arrived in Brussels for marathon budget negotiations.
The Prime Minister said he would be fighting "very hard" for a good deal for British taxpayers and to keep the rebate negotiated by Margaret Thatcher in the 1980s.
"These are very important negotiations. Clearly at a time when we are making difficult decisions at home over public spending it would be quite wrong - it is quite wrong - for there to be proposals for this increased extra spending in the EU.
"So we are going to be negotiating very hard for a good deal for Britain's taxpayers, for Europe's taxpayers, and to keep the British rebate."
Mr Cameron is calling for a real-terms freeze, or even a cut, in the budget for 2014-20 - the sole subject on the agenda for the summit which starts later and may run into the weekend.
Mr Cameron is the first in line for a meeting with European Commission president Jose Manuel Barroso and European Council president - and summit chairman - Herman Van Rompuy. Other EU leaders will be ushered in throughout the day as part of an unusual effort to avoid deadlock when the summit gets under way over dinner.
Mr Cameron wants at least a real-terms freeze in EU spending, if not actual cuts, and to retain in full Britain's EU budget rebate worth nearly £3 billion a year off the UK's annual contributions to Brussels.
A pre-summit compromise is already on offer - a seven-year budget "envelope" of 940 billion euros (£756 billion) for 2014/2020 - a cut of nearly 5 billion euros (£3.8 billion) compared with the 2007/2013 ceiling.
The move was seen in Downing Street as being in the right direction - although the "cut" is in a spending ceiling which officials say has not been reached. It is also above the 886 billion euros (£712 billion) originally pitched by the Treasury as in line with the real-terms freeze Mr Cameron wants.
But in the complex world of EU budget economics, with financial "commitments" different from "payments", a range of calculation options, rebates for some countries, and contributor and beneficiary member states, Mr Cameron and his colleagues have plenty of scope for claiming summit success.