Dominic Raab has resigned as the UK’s deputy prime minister after an independent report into bullying claims against him upheld two of the allegations.

Raab, who was also justice secretary, issued a letter on Twitter on Friday morning saying he wanted to “keep his word” having promised to resign if the inquiry by employment lawyer Adam Tolley found evidence of any bullying.

But in his defiant letter he warned that the inquiry would undermine the ability of ministers to “exercise direct oversight” over civil service officials.

“In setting the threshold for bullying so low, this inquiry has set a dangerous precedent,” he wrote. “It will encourage spurious complaints against ministers and have a chilling effect on those driving change on behalf of your government — and ultimately the British people.”

Prime minister Rishi Sunak commissioned Tolley to carry out an inquiry into Raab’s behaviour after following reports in November that the deputy prime minister was facing multiple fresh complaints of bullying behaviour as justice secretary and previously foreign secretary.

Tolley is understood to have examined eight formal complaints involving allegations by over 20 officials.

This is a developing story