Michael Gove has revealed that David Cameron feels "annoyed and let down" with him because he campaigned against Downing Street over Brexit.
Mr Gove, who was sacked as justice secretary by Theresa May, said he had expected the Leave side to lose the EU referendum in June, and thought Mr Cameron would stay on as prime minister if Brexit won.
The Tory MP admits his former close friendship with Mr Cameron has been put under immense strain by his decision to back Leave.
"I haven't talked to him for a while and, I think - in fact I am pretty certain - he feels annoyed and let down, and that's a shame. Because I have nothing but respect and admiration for him.
''But also, we were in a referendum campaign, I was on a different side, he lost and I think he is entitled to feel anything between upset or more so. I'll always defend him from anyone who criticises him," Mr Gove told The Times.
On referendum night, Mr Gove recalls: "I went to bed thinking that we'd lost, and therefore that David would be prime minister the next day, and for days, months and weeks to come after.
"It's not true that we didn't have a plan for what to do on Britain leaving. It is the case, though, that I didn't have a plan for, or thought what would happen if, David Cameron resigned immediately."
However, Mr Gove states that he and Boris Johnson discussed who would run for Mr Cameron's job in the days leading up to the referendum, adding: "And on the Friday, after the vote, about lunchtime-ish, Boris said, 'Do you want to run? If you do, you know, fair enough.' And I said, 'I don't, really.' And he said, 'Oh, I'm thinking of it. Will you support me?' And I said, 'Can I wait for a day to think about it and let you know?'"
Mr Gove says that Mr Johnson felt "hurt" by his last minute decision to quit his Brexit ally's leadership bid and stand against him.
"I should either not have been so eager to back him in the first place and waited, or, having backed him, even with doubts and concerns, I should have stuck with it.
"But understandably, given the leadership fallout, he felt hurt. But since then, he's been very civilised, actually."
Asked if the pair still speak, Mr Gove said: "Very occasionally. And he's been nothing but gracious."