Philip Hammond is challenging Boris Johnson to prove he is not trying to “dupe” MPs into backing a “heavily camouflaged” no-deal Brexit before the crunch Commons vote on the prime minister’s deal.

The former Tory chancellor, who had the whip withdrawn for voting to oppose no-deal, called on Mr Johnson to give assurances that he wanted a high-ambition future trade relationship with the European Union.

Splits have emerged in the group of MPs expelled from the Conservative Party last month, with David Gauke, the former justice secretary, becoming the latest high profile figure to say he would back the deal.

Writing for The Times, Mr Hammond suggested he would vote against the Brexit deal unless the government demonstrates that it will not use the