The Government is reportedly prepared to pay €20bn (£17.7bn) to meet its financial obligations to the European Union after Brexit.
According to the Financial Times, Theresa May will include the offer in her much-anticipated Brexit speech on Friday in Florence.
Mrs May’s top EU adviser Oliver Robbins told his counterparts in EU capitals, including Berlin, that the offer would be included in the Prime Minister’s address, the report says.
Downing Street has dismissed it as “pure speculation about a speech that has not yet been given”.
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The so-called Brexit bill has emerged as a main stumbling block in divorce talks with Brussels, and Mrs May might look to break the deadlock with a financial offer.
No figure so far has been floated by the British Government or the EU. If confirmed, the €20bn figure might be significantly lower than what Brussels reportedly wants – around €60bn (£53bn)
The Government has said the time of big sums of cash going to the EU ends with Brexit, but has acknowledged in principle that it will make a payment.
Downing Street has been tight-lipped about Mrs May’s speech, seen as the most important intervention on Brexit since her Lancaster House address in January.
It comes amid reports of a split in the Cabinet over the Brexit strategy, after Boris Johnson wrote an explosive 4,000-word newspaper article setting out his own vision for the divorce.
Mr Johnson’s blueprint calls for a clean-break Brexit that envisages no payments to gain access to the European single market.
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The intervention prompted calls for Mrs May to sack the Foreign Secretary over the breakdown in Cabinet discipline, as well as reports Mr Johnson might be ready to resign if his vision is not heeded in Mrs May’s speech.
Both sides have sought to play down the row.
Mr Johnson has dismissed speculation he might resign this weekend, telling the Guardian newspaper that he was “mystified” by the suggestion.
“It feels to me like an attempt to keep the great snore-athon story about my article running. I think that is what is going on,” he was quoted as saying.
“I am confident she will set out an exciting and positive vision for Brexit and it will be a speech around which everyone can unite.”
Mrs May has said the Foreign Secretary is doing “good work” and will stay on in the Cabinet.
The PM will discuss details of her speech at a Cabinet meeting on Thursday.
In a show of unity, Mr Johnson is expected to travel to Italy for the speech.