Jeremy Hunt has secured the support of Defence Secretary Penny Mordaunt in his bid to be Conservative Party leader.
Mordaunt is the most senior Brexiteer in the current cabinet and winning her backing is a coup for the foreign secretary.
Speaking at Hunt’s campaign launch in central London on Monday morning, she said: “I trust him on Brexit.”
Mordaunt has long been seen as likely to enter the race to succeed Theresa May herself.
But throwing her weight behind Hunt today, she said he had “credibility from all sides” in the Brexit debate. “I believe he has the experience, the values, and a plan,” she added.
“He has the humility to understand that outside of Westminster there are millions of people without a Conservative Party membership card who are watching us choose their prime minister.”
Mordaunt said the next PM needed to “plug the financial hole” in the defence budget.
And in his campaign speech today Hunt promised to increase the proportion of the UK’s GDP spent on the military.
Boris Johnson is seen as the frontrunner in the contest which formally got underway today.
Hunt has emerged as one of the most likely candidates to win enough support from Tory MPs to take on Johnson as one of the final two candidates voted on by party members.
It comes as Michael Gove’s campaign got off to a difficult start after he confessed he had used cocaine 20 years ago.
Hunt also used his speech to warn his party it would be “annihilated” if the party fights a general election before delivering Brexit.
“Our failure to deliver Brexit has put our country and our party in grave peril,” he said.
“The leadership I offer is based on one simple truth: without Brexit there will be no Conservative government and maybe no Conservative Party.”