James Chapman, a former political editor of the Daily Mail who was special adviser to Mr Davis from the creation of the Department for Exiting the EU, suggested centrist MPs could form a new bloc to seize the balance of power at Westminster.
Naming Scottish Conservative leader Ruth Davidson as potential key player in any pro-EU political alliance, he suggested a new party would grant a second Scottish independence referendum which nationalists would “lose much worse than last time”.
“Past time for sensible MPs in all parties to admit Brexit is a catastrophe, come together in new party if need be, and reverse it,” he said in a string of tweets.
Mr Chapman, who also served as special adviser to ex-Chancellor George Osborne, suggested the economic impact of Brexit would require a decade of “punishment budgets” to repair the public finances, and claimed the government had not begun any work to prepare for new customs checks between the UK and EU.
He also directed a series of messages to other cabinet members over the possible impact of Brexit, challenging Transport Secretary Chris Grayling to “confirm airlines won’t be able to sell 80% of flights from next March” and asking Health Secretary Jeremy Hunt if there was “any update on how millions of UK tourists in [the] EU will maintain right to emergency healthcare”.
Suggesting a “the Democrats” as a possible name for a new centrist grouping, Mr Chapman said their “priority” would be “getting up noses of Brexit jihadis”.
Mr Chapman, who quit government in May to join PR firm Bell Pottinger, named Tory MPs Anna Soubry, Grant Shapps and Mark Harper as possible defectors to a new political group, saying they had more in common with Labour’s Rachel Reeves and Liberal Democrat leader Vince Cable than their own party.
And he even carved out a possible role for former Lib Dem leader Nick Clegg’s wife Miriam Gonzalez Durantez - as a future foreign secretary.