LONDON (AP) — UK Deputy Prime Minister Dominic Raab grudgingly resigned Friday after an independent investigation found he bullied civil servants, though he criticised the report as “flawed.”

Raab’s announcement came the day after Prime Minister Rishi Sunak received the findings of an investigation into eight formal complaints that Raab, who is also justice secretary, had been abusive toward staff members during a previous stint in that office and while serving as Britain’s foreign secretary and Brexit secretary.

Attorney Adam Tolley, who conducted the inquiry, said Raab “acted in a way which was intimidating,” was “unreasonably and persistently aggressive” and “introduced a punitive element” to his leadership style.

“His conduct also involved an abuse or misuse of power in a way that undermines or humiliates,” Tolley wrote in the 48-page report. “His conduct was bound to be experienced as undermining or humiliating by the affected individual, and it was so experienced.”

Raab, 49, denied claims he belittled and demeaned his staff and said he “behaved professionally at all times,” but said he was resigning because he had promised to do so if the bullying complaints were substantiated.

The investigation made two findings of bullying against him and dismissed the others, Raab said in his resignation letter. He called the findings “flawed” and said the inquiry “set a dangerous precedent” by “setting the threshold for bullying so low.”

Raab said he quit because he was “duty bound” to resign since he had promised to.

Sunak said he accepted the resignation “with great sadness,” in a letter that praised much of the work Raab had done. He also referred to “shortcomings” in the investigation, which he said had “negatively affected everyone involved.”

The resignation spared Sunak the difficult task of deciding the fate of his top deputy.

If he had fired Raab, he would have opened himself to criticism for appointing him in the first place despite reportedly being warned about Raab’s behaviour; if he had kept him in the job, he would have been criticised for failing to follow through on his promise to restore integrity to the Conservative government.

Sunak received the investigation report Thursday morning and didn’t immediately make a decision. Spokesperson Max Blain, speaking before Raab’s resignation, said Sunak still had “full confidence” in Raab while he reviewed the report.

The ministerial code of conduct requires ministers to treat people with respect and have proper and appropriate relationships with colleagues, civil servants and staff. It says harassment, discrimination and bullying will not be tolerated.