Ivan Rogers outside the House of Commons after appearing before a select committee | Daniel Leal-Olivas/AFP via Getty Images EU will demand exit bill, former UK ambassador warns Ivan Rogers says UK’s departure will create ‘immense’ financial difficulties for the EU.

LONDON — European leaders believe Brexit “exploded a bomb" underneath the EU’s budget and they will “care passionately” about securing an exit bill of up to €60 billion from the U.K., the former British ambassador to the EU warned Wednesday.

Sir Ivan Rogers, who resigned last month, criticizing “muddled thinking” in government, said the U.K.’s departure would create “immense” financial difficulties for the EU.

He said reports that EU leaders were considering demanding up to €60 billion from Britain were “genuine” and would become a major sticking point in negotiations after the triggering of Article 50.

Giving evidence to MPs on the House of Commons European scrutiny committee, Rogers predicted that the EU27 would first seek to negotiate the scope of Article 50 talks, but would then turn to the question of the exit bill.

“I think it’s important that you all understand that from an EU perspective, however much we dispute this … they will think, they do think, many have said to me, ‘you’ve exploded a bomb underneath the multi-annual financial framework,’" Rogers told MPs, referring to the seven-year financial framework that runs from 2014 to 2020.

"Many have said to me, 'you’ve exploded a bomb underneath the multi-annual financial framework’" — Ivan Rogers

While he said that the U.K.’s financial liabilities to the EU, in terms of budget commitments and pension contributions for EU employees, could be used as “leverage” by British negotiators, it could also unite EU member countries in a hard-line approach.

He said one diplomat from a “poorer Central Eastern European member state” had told him that Brexit would force his government to tell its citizens that the country would be receiving less EU funding than hoped.

“The reality for them on the ground … is that they have told their people that structural funds receipts of quantum X will be available until 2020,” he said. “And that figure, merely by dint of U.K. exit and us not paying anymore, is diminished by 10 or 12 percent. So they’ve got to go to their own citizens and say: ‘Whoops! When I was saying to you you’re going to get 100, you’re now going to get 88.”

Meanwhile, taxpayers in member countries that are net contributors to the EU, such as Germany and the Netherlands, could resent having to cover the bill for Britain’s liabilities, he predicted, creating a united position among richer and poorer EU states that the U.K. must pay.

The prospect of paying a large exit bill is anathema to Euroskeptics in Prime Minister Theresa May’s Conservative party, and will be difficult for her to sell at home. May has said the U.K. should no longer have to pay "huge sums" into the EU budget after leaving the single market, but it could pay an "appropriate contribution" to remain involved in certain EU programs.

Asked what would happen if the U.K. refused to agree to demands on financial liabilities, Rogers suggested such a stance could kill a preferential trade deal with the EU.

Rogers added that the view among many EU leaders was that leaving the bloc with no deal and relying on World Trade Organization rules, as May has said she is prepared to do, would be so “unpalatable” for the U.K. that the prime minister will not risk it.