A leaked draft copy of the bloc's negotiating strategy outlines discussion of suing the UK by bringing Britain before the International Court of Justice at the Hague.
Both the Prime Minister's legal advisers and a House of Lords committee have found Britain has no legal obligation to pay the settlement – which includes fees to back up the EU's pension scheme.
But in the EU negotiation papers, one official is quoted as saying “see you in The Hague” in reference to the British decision not to cough up the multi-billion pound bill.
The draft document is also believed to reveal the bloc is prepared to drive a tough bargain on Brexi
The draft document is also believed to reveal the bloc is prepared to drive a tough bargain on a hard Brexit – demanding free movement of people, capital, goods and services in exchange for access to the single market.
It comes after claims Philip Hammond will refuse to “recognise” the divorce bill put forward by the EU.
Sources close to the Chancellor claim Mr Hammond will ignore the massive payout, chiming in with the Prime Minister and Brexiteer-in-chief Boris Johnson, who claimed the bloc’s demands were unreasonable.
Eurocrats are believed to have threatened to take Britain to the Hague Fishermen need Brexit now! Mon, March 20, 2017
Cornwall fisherman says EU is killing his industry
Express.co.uk 1 of 9
Over the weekend, the Chancellor accused Brussels of "overstating" its position ahead of the negotiations, which will begin after Theresa May invokes Article 50 on March 29.
A source close to Mr Hammond added: "We don't recognise the 60 billion euros.”
The Foreign Secretary has already publicly urged Mrs May to resist a large payment, while International Trade Secretary Liam Fox dismissed the idea as "absurd".
Get Quotes on Home Insurance
Advisers have claimed the UK does not owe the bloc a penny of the bill
heresa May is set to demand any payments include a £9billion refund
And Theresa May is set to demand any payments include a £9billion refund for British money paid into the EU’s coffers.
The Tory leader is expected to remind Eurocrats Britain is owed the money, currently being held by the European Investment Bank, after the triggering of Article 50.
The bill is likely to be dented by the British-owned cash currently caught up in the Brussels bureaucracy.