Philip Hammond has already scrapped his predecesor’s plans to eradicate the budget deficit by 2020

Ministers will have to borrow at least £60 billion more than planned between now and the end of the parliament because of Brexit, according to a leading economist.

The forecast highlights the extent to which the vote to leave the EU has undermined the government drive to reduce borrowing, a central theme of the Tory 2015 general election campaign.

The decision to abandon plans to eradicate the budget deficit by the end of the parliament and abandon fiscal tightening means that Philip Hammond, the chancellor, is likely to have cash for a growth package in the autumn statement. This could be worth £15 billion to £25 billion, according to the new analysis.

Alan Clarke, an economist at Scotiabank, forecasts the deficit will be £7 billion