Philip Hammond has been accused of undermining Theresa May's Brexit strategy after warning on Thursday that leaving the European Union without a deal will have "large fiscal consequences" for Britain.

Dominic Raab, the Brexit Secretary, had attempted to play down the risk of a no-deal Brexit as part of a choreographed Government strategy, saying that the "vast majority" of consumers will not even notice the impact.

However within hours of Mr Raab's speech Philip Hammond, the Chancellor, published a letter to the Treasury select committee warning that a no-deal Brexit could increase borrowing by £80billion a year by 2033.

The Telegraph understands that Mr Hammond published the letter without clearance from Downing Street, who were infuriated by his intervention.

A Downing Street source said that the analysis highlighted by the Chancellor was "preliminary and very much a work in progress", adding No 10 "does not clear minister's correspondence with fellow MPs".

Mr Raab was also unaware of Mr Hammond's intervention. A Government source added: "This was a deliberate intervention by Philip, he knew exactly what he was doing."