On top of previous demands such as a "fair but inferior deal" for the UK,  the EU now wants a €20 billion divorce settlement as the UK's "fair share" of inane projects the UK agreed to as part of the EU.

EU officials insist the UK is on the hook for past spending commitments.

"Money has long been the subject of the most ferocious political fights in Brussels and the Brexit divorce — and Britain's legacy bill of as much as €20bn — is shaping up to be one of the most epic of them all.

At the heart of the debate is a question about the nature of the bloc. Is it a club where a member's liabilities expire on withdrawal or one where a member honours its promises even after it leaves?

For the EU-27 the answer is clear. One official compared it to Britain signing a five-year gym membership then asking for its money back after three. Another senior diplomat said it was like Britain "sitting at the restaurant, picking from the menu, then leaving before the bill arrives".