In a public letter, Zahawi said he was “hurt” that Johnson would not listen to his advice as a friend of more than 30 years. “Prime Minister: this is not sustainable and will only get worse: for you, for the Conservative party and most importantly for the whole country. You have to do the right thing and leave now,” he said, but he did not resign. Michelle Donelan, the education secretary appointed this week, also resigned, saying the cabinet needed to force Johnson’s hand. He followed Brandon Lewis, the Northern Ireland secretary, who also resigned on Thursday morning. Nadhim Zahawi’s letter to Boris Johnson. Photo: Nadhim Zahawi/PA Lewis said: A decent and responsible government is based on honesty, integrity and mutual respect – it is with deep personal regret that I have to leave government as I no longer believe these values are upheld.” The latest developments make it increasingly likely that Johnson will not be able to see out the day as prime minister, despite the No 10’s insistence on Wednesday night that he wanted to “fight on”. Subscribe to First Edition, our free daily newsletter – every morning at 7am. BST