Penny Mordaunt has rejected a call by Boris Johnson to pull out of the Tory leadership race and back him in another blow to his prospects of returning to Downing Street.
Sources close to the Commons leader told Sky News she had spoken to the former prime minister today.
Several long-time allies of Mr Johnson, including Suella Braverman and Steve Baker, threw their support behind Rishi Sunak, the frontrunner in the race, on Sunday.
Blow to former PM as old ally backs Sunak – politics latest
Mr Baker, the former head of backbench Brexiteers, warned that a potential comeback by the former prime minister would be a “guaranteed disaster”.
Although Mr Johnson has not officially entered the race, his offer to Ms Mordaunt implies he may not have the backing of the 100 MPs he needs to go through to a vote by the party membership.
But Ms Mordaunt has chosen to stick with her own campaign, and earlier insisted she was “in it to win it”.
Those wanting to make the final ballot to win the keys to Number 10 only have until 2pm on Monday to secure nominations from at least 100 Tory MPs.
Ms Mordaunt confirmed she was running on Friday and so far has 24 members publicly backing her, while Mr Johnson has 59.
Both are far behind former Chancellor Rishi Sunak, who had already reached the threshold before announcing he was running on Sunday – and now has 142 supporters.
If all three make it through the first stage of the leadership contest, Tory MPs will vote to chose their favoured candidate.
However, if they fail to unite behind one person, the decision will fall to the wider party membership to decide between the two most popular PM hopefuls.
Mr Johnson was also understood to have held talks with Mr Sunak last night amid rumours they were trying to come to a deal over the leadership – but the meeting appears to have come to nothing.