Rishi Sunak was unaware of “any specific allegations” against Gavin Williamson, a No 10 ally has said, as the prime minister faces further scrutiny over his judgment in bringing him back to the cabinet. Williamson resigned as a Cabinet Office minister on Tuesday after the Guardian revealed claims that while he was defence secretary he told a former senior civil servant to “slit your throat”. It followed allegations he sent expletive-laden messages to the former conservative chief whip Wendy Morton complaining about not being invited to the Queen’s funeral. Sunak accepted Williamson’s resignation with “great sadness” but added that he supported his decision to stand down. On Wednesday, the education secretary, Gillian Keegan, said that Williamson “acted quickly” in resigning from the cabinet after a fortnight in office as he was subject to claims of bullying. She said Sunak possessed the “highest degree of integrity and judgment” despite bringing the twice-sacked minister back into government while knowing of a complaint against him. “People make their decisions based on the mix of talent they want in, the mix of people they want. This happens in politics all the time,” Keegan told BBC Radio 4’s Today programme. “You know, people come back and forth.” “The reality is you appoint people and, you know, the only thing you can do if things don’t work out or things go wrong or things come to light afterwards is act quickly. Gavin’s acted quickly, he’s removed the distraction,” Keegan added. Ahead of his appearance at prime minister’s questions on Wednesday, Keegan said Sunak knew only about a “disagreement” between Williamson and Morton when handing him a role in the Cabinet Office. “He didn’t know about any specific allegations, he hadn’t seen any text messages or anything like that,” she told LBC radio. The shadow foreign secretary, David Lammy, questioned why Sunak appointed Williamson in the first place despite knowing of the complaint. “I think this raises real questions about the prime minister’s judgment. The behaviour that we’ve heard about in the last few days is repellent, it’s odious and it’s quite, quite unacceptable,” he told Today. “He appointed him as some sort of enforcer, apparently, because this is the way he behaves. This is weak. It’s unacceptable. We really should have an account of why he came back into government.” Labour’s deputy leader, Angela Rayner, suggested Williamson should quit as an MP if he was found to have bullied colleagues or officials. “There’s no place for bullies in parliament,” she told BBC Two’s Newsnight on Tuesday. She said Sunak appointed Williamson “with full knowledge of serious allegations about his conduct and repeatedly expressed confidence in him”. “This is yet another example of Rishi Sunak’s poor judgment and weak leadership,” she added. The Liberal Democrat deputy leader, Daisy Cooper, said: “Rishi Sunak has serious questions to answer about why he appointed Gavin Williamson, then stood by him instead of sacking him.” Williamson is facing three separate inquiries into his behaviour, two with parliament’s Independent Complaints and Grievance Scheme (ICGS) and the other an internal Conservative party investigation. Two relate to the same incident involving Morton. At PMQs, Sunak will face pressure to explain why he gave Williamson a senior role in government after he had already been sacked by Theresa May and Boris Johnson. Williamson was sacked first by May as defence secretary in 2019 for leaking details of a national security council meeting, and then by Johnson as education secretary over A-level results during the Covid pandemic. Keegan defended Sunak’s expression sadness over thedemise of his close political ally, saying the family of the civil servant who claims Williamson told them to “slit your throat” should welcome “compassion” as the government scandal involved “people with families”. “I think it’s always sad when a colleague resigns. It does have an impact on them personally, it has an impact on their family. So, you know, nobody takes glee out of these situations at all,” she told Times Radio.