Britain's withdrawal from the European Union could leave the remaining 27 countries with a 20-billion-euro hole in their budget to fill, a commissioner said Wednesday, June 28, AFP reports.

EU Budget Commissioner Guenther Oettinger, of Germany, called on the bloc to improve the efficiency of its spending in the wake of Brexit in March 2019.

"We won't have the UK with us any more, but they were net payers despite the Thatcher rebate, so we will have a gap of 10 to 11 billion euros a year," Oettinger told a press conference as he unveiled the commission's proposals for the budget.

Under late British prime minister Margaret Thatcher Britain secured an annual rebate on its budget contribution worth more than three billion euros.

Oettinger wrote separately in a blog on the proposals that "at the same time we need to finance new tasks such as defence, internal security... The total gap could therefore be up to twice as much."

The EU's budget in 2017 was 157.9 billion euros.

The German commissioner said that the EU could, after Britain leaves, save money by eliminating all rebates enjoyed by a number of other countries.

As part of Brexit negotiations that began this month, the EU 27 are demanding that Britain pay an exit bill of up to 100 billion euros to honour commitments made while it was a member.