Theresa May has slapped down claims from the Chancellor that a ‘no deal’ Brexit could cost £80 billion, implying the figure was not reliable and insisting a clean break with the bloc “wouldn’t be the end of the world”.

Chancellor Philip Hammond warned Thursday that the Treasury could be forced to borrow £80 billion extra over 15 years as a result of Britain leaving without a deal.

However, the Prime Minister hit back saying she believed Mr Hammond was talking about old figures from January, adding: “They were a work in progress at that particular time.”

She made the comments to reporters as she kicked off a three-day trip to Africa, reported by The Guardian.

Mrs May also referred to comments from the Director General of the World Trade Organization (WHO) Roberto Azevêdo, who said that a clean Brexit “is not going to be the end of the world in the sense that trade is going to stop and that everything is going to fall down”.

But “it’s not going to be a walk in the park either”, he said.

Mentioning Azevêdo’s comments, the Prime Minister told reporters during a visit to South Africa:

“Look at what the director general of the World Trade Organization has said. He has said about the no-deal situation that it will not be a walk in the park, but it wouldn’t be the end of the world.”

She added: “What the government is doing is putting in place the preparation such that if we are in that situation, we can make a success of it, just as we can make a success of a good deal.”

Ahead of the Africa trip, Mrs May also said she would be “unashamed” to use part of the UK’s massive foreign aid budget to boost trade with the continent after Brexit.

“I am unashamed about the need to ensure that our aid programme works for the UK,” Mrs May said, according to The Times.

“So today I am committing that our development spending will not only combat extreme poverty but at the same time tackle global challenges and support our own national interest.

“This will ensure that our investment in aid benefits us all, and is fully aligned with our wider national security priorities.”