David Cameron has laid out an ambitious battle plan to secure a new British relationship with Europe as he called for cuts in the senior commission payroll, and warned he was prepared to veto increases in the new long-term EU budget.

Speaking at the close of an EU summit devoted to banking union, he signalled he was opening a fresh front by arguing that commission plans for a new euro-area budget should justify a smaller budget for the EU as a whole, a proposal rejected at the summit by many EU partners.

Cameron, describing the British approach as gritty and realistic, is entering the most turbulent period of his relations with Europe as he prepares to fight over the EU budget at a summit in November, and then to protect the City's interests at a further summit in December. In the interim he plans a major speech setting out his intention from 2014 to renegotiate the UK relationship with Europe, and then put this to a referendum in the UK after the general election.

Cameron insisted the plates in Europe were moving, and the opportunity now existed to negotiate a fresh settlement with the rest of Europe.

The most immediate bruising talks over the next seven-year EU budget settlement start at the summit in November, and on Friday he laid down a marker by targeting the top-earning commission officials. He said: "There are 16% of employees in the commission earn over €100,000. What we have done in Britain is crack down on central administration, on costs in Whitehall and on the numbers of people employed, to release money for things that are more important. We need to see in the EU budget proposals that sort of rigorous approach. There is a deal that can be done but it cannot involve spending a lot more money."

There are 55,000 EU staff in total. The average salary across EU institutions is €102,000, according to British sources.

A letter from the eight countries which pay more into the EU budget than they get out of it in benefits claimed this week that the European commission was demanding a 26% increase to pay for the costs of its civil service for the next seven-year budget period.

Britain can veto the seven-year budget due to start in 2014, and Cameron promised a tough approach. He said: "It would be good to have a deal, but it would not be acceptable to see some huge increase in EU spending at a time when other budgets are being cut. If there is not a deal that is good for Britain, then there won't be a deal."

He also insisted opportunities lay ahead to renegotiate the British relationship with its EU partners by seeking treaty changes. The Foreign Office is conducting a detailed review of the balance of competences between the UK and EU. He said: "I don't accept that the EU is fixed and stuck in one track. It is changing and you can see it changing right now as the eurozone has to integrate more quickly."

Pointing to the greater integration of the eurozone, and the likelihood of a euro-area budget, he said: "The plates of Europe are moving and changing. Just as the eurozone is changing, and there are fresh settlements there, so there are fresh opportunities for Britain as well."

He argued: "As the eurozone develops and integrates … there are opportunities opening up for a new settlement between Britain and Europe, and there will be opportunities to seek that new settlement and to get fresh consent for that settlement. I am keen to do that."