LONDON (Bloomberg) - Foreign Secretary Boris Johnson backed down from his previous rhetoric and accepted that Britain will have to pay as it leaves the European Union, joining other senior Brexit-backers in agreeing to the idea of a multi-year "transition" for a smoother split.

In July, Mr Johnson said the sums of money that it was reported the EU wanted from the UK were "extortionate" and that Brussels could "go whistle" for the money.

Speaking on Friday (Aug 25), he said this had been a reference to the idea of a €100 billion (S$160.52 billion) bill.

"Of course we will meet our obligations," Mr Johnson told the BBC. "We are law-abiding, bill-paying people. We will certainly have to meet our obligations."

He also accepted the idea of a transition period as Britain departs the EU, something on which he had previously been silent.

"My view is that we should get on," he said, adding that businesses craved certainty and an orderly divorce. "What business would want us to achieve is speed and efficiency."