Sir Alan Duncan has resigned as minister of state for Europe and the Americas ahead of Boris Johnson’s Tory leadership contest win.
The pro-European minister has previously voiced his opposition to Johnson, who is expected to be named as the new prime minister tomorrow.
Duncan’s departure is the first of a string of mooted resignations, as ministers opt to step down instead of serving under Johnson.
Chancellor Philip Hammond yesterday confirmed he will quit before Johnson moves into number 10, citing concerns over the frontrunner’s commitment to a no-deal Brexit.
Justice secretary David Gauke has also announced that he will resign in protest, saying a no-deal scenario would be a “national humiliation”.
It follows the resignation of digital minister Margot James, who last week blasted the future prime minister’s strategy for leaving the EU as “reckless”.
Hammond has emerged as a leader in a campaign to derail Johnson’s Brexit plans, saying he will campaign from the backbenches to allow parliament to block a no-deal exit. However, he stopped short of saying he would support a vote of no confidence in a Johnson government.
In addition to resignations, a handful of disgruntled Tories are said to be mulling a defection to the Liberal Democrats in a bid to deprive Johnson of a parliamentary majority.
Johnson is expected to defeat rival Jeremy Hunt and be named as Britain’s next prime minister tomorrow morning.
The new prime minister will take office on Wednesday afternoon after Theresa May’s final PMQs.
This is a breaking news story. More to follow shortly.