The speech will focus on what kind of ties Britain wants to have with the EU after it leaves the bloc in March 2019 - something British negotiators have been keen to discuss with a so-far reluctant Brussels.

“The prime minister wanted to give a speech on the UK’s future relationship with Europe in its historical heart,” May’s spokesman told reporters.

“She will underline the government’s wish for a deep and special partnership with the European Union once the UK leaves the EU.”

Negotiations on the terms of the divorce with the EU have made limited progress since May started a two-year countdown to Brexit. That has prompted warnings from the EU that discussions on the future relationship between the two could be pushed back from their intended start time of October.

The September round of Brexit talks has been pushed back by a week until the end of the month, in what EU diplomats said was a move designed to allow May to make her speech. Britain said the rescheduling was to allow both sides more time to make progress.

May’s speech could add weight to the British push to move talks forward, which ministers say is a crucial step in providing certainty for businesses worried about how Brexit will affect their ability to trade across borders.

Her choice of venue - a city celebrated as the birthplace of the Renaissance period and made wealthy by international trade and banking - is a nod to the kind of free-trading relationship Britain wants to maintain with Europe and develop globally.

Sceptics have said the British approach amounts to cherry picking the benefits of EU membership without paying for them.

“The UK has had deep cultural and economic ties spanning centuries with Florence - a city known for its historical trading power,” the spokesman said.

“As the UK leaves the EU we will retain those close ties. As the prime minister has said many times, we are leaving the EU, not Europe.”

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