British Prime Minister Rishi Sunak on Wednesday agreed to a request by his deputy and close Cabinet ally, Dominic Raab, to set up an independent investigation after two formal complaints of bullying were filed against him by civil servants.

Raab is the UK's Deputy Prime Minister and Justice Secretary and filled in at Prime Minister's Questions (PMQs) in the House of Commons, while Sunak is in Indonesia for the G20 Summit.

Raab denied the allegations against him and told Parliament that he would "comply fully" with the independent investigation.

"Integrity, professionalism and accountability are core values of this government. It is right that these matters are investigated fully," said Sunak.

"I know that you will be keen to address the complaints made against you and agree that proceeding in this way is the right course of action," he said, in his reply to Raab's letter requesting an independent inquiry.

In his letter to Sunak, the senior Conservative Party MP said the complaints related to his time as justice secretary and foreign secretary under former Prime Minister Boris Johnson.

Sunak's spokesperson at 10 Downing Street confirmed an independent investigator, who is not from the civil service, will be appointed to lead the inquiry. However, the Prime Minister, as the "ultimate arbiter" of the ministerial code, will have the final say over the findings of the inquiry.

"It is important we have zero tolerance for any bullying," Raab said in the House of Commons.

"I am confident that I have behaved professionally throughout. But immediately I heard that two complaints had been made I believe they were made yesterday (Tuesday, I was notified this morning (Wednesday) I immediately asked the Prime Minister to set up an independent investigation. And of course, I will comply with the investigation fully," he said.

Over the past week, Raab has faced a spate of bullying allegations in the UK media, including allegedly throwing tomatoes at staff, being rude to staff and being warned about his behaviour.

"I have always sought to set high standards, and forge teams that can deliver for the British people amidst the acute challenges that we have faced in recent years," his letter to Sunak reads.

"I have never tolerated bullying, and always sought to reinforce and empower the teams of civil servants working in my respective departments," it reads.

Raab, who had backed Sunak in the leadership contest to replace Boris Johnson, was sacked as justice secretary and deputy prime minister when Liz Truss won the race in September. He was soon reappointed to both roles as Sunak was elected as Conservative leader by the party's MPs last month.

The latest episode marks another close ally of Sunak under pressure over bullying allegations, after former education secretary Gavin Williamson resigned from the Cabinet earlier this month pending an investigation into allegations of abusive behaviour towards staff against him.

PTI