THE Treasury was accused of writing a “blank cheque” to EU nationals in the Brexit deal on child benefit.

Ex-Cabinet Minister Priti Patel said the Government’s deal with Brussels appeared to suggest social security payments for overseas workers will not change after Brexit.

The Government paid out an astonishing £879million in the welfare benefit to 572,000 EU nationals in 2015-2016.

And Treasury Chief Secretary Liz Truss has told MPs that it is too expensive now to calculate how much could be paid out in child benefit in the 15 years after Brexit.

In a written Parliamentary answer she says the figure could only be provided at a “disproportionate cost”.

Former Cabinet Minister Priti Patel stormed: “This betrays the Treasury’s real priorities.

“It raises serious questions that they spend time peddling doomsday economic forecasts while lacking the ability to know how and to whom taxpayers’ money will be spent in the coming years.”

She added: “I call on the Chancellor to be honest with Sun readers and tell them how much we’ll be spending on foreign benefit claimants in the coming years.”

Last month the Government published a mammoth economic analysis of Brexit options – all predicting growth and the hit to the public finances over the next 15 years under four different Brexit scenarios.

Under Theresa May’s controversial deal with the EU, EU nationals will keep their rights to healthcare, pensions and “other social security benefits”.

Arch Eurosceptics have complained that even ex-PM David Cameron’s doomed renegotiation managed to wrestle an ‘emergency brake’ on welfare out of Brussels.

A Government spokesman said: “A HMG spokesperson said; ‘We have agreed a deal in principle with the EU that will protect access to benefits for British people living in the EU, as well as those EU nationals living in the UK who are within the scope of the Withdrawal Agreement.

“Our balanced approach is keeping welfare spending at sustainable levels so that it protects the most vulnerable while being fair to the taxpayers who fund it.”