Dominic Raab faces a third formal complaint in bullying probe

UK's Deputy Prime Minister is alleged to have bullied officials and behaved in a rude and demeaning way in previous cabinet roles

British Deputy Prime Minister Dominic Raab. EPA

An investigation into claims of bullying by Britain’s Deputy Prime Minister has been expanded.

Downing Street confirmed on Friday the scope of the probe into Dominic Raab’s conduct has been widened to include a third formal complaint.

It relates to his tenure at the former Department for Exiting the European Union, Prime Minister Rishi Sunak’s spokeswoman Camilla Marshall told reporters on Friday.

She said: "I can confirm that the Prime Minister has now asked the investigator to add a further formal complaint relating to conduct at the Department for Exiting the European Union and to establish the facts in line with the existing terms of reference."

The new complaint was received by the Cabinet Office on Wednesday, she said, adding that the Prime Minister retains confidence in his deputy.

The other two complaints against Mr Raab were lodged last week but date from his previous tenure as justice secretary and his time as foreign secretary.

Over the weekend, reports emerged that Mr Raab’s refusal to speak to some foreign office staff cause a “blockage” during the evacuation of western forces from Afghanistan last year.

The Deputy Prime Minister is said to have had a poor working relationship with certain senior officials who he viewed as “time wasters,” and only allowed only a small number of senior staff to engage with him and his private office.

That reportedly caused some decisions in the final stages of the UK withdrawal to be “delayed and backed up,” according to an article in The Guardian.

He has said he is confident he behaved professionally throughout, but will “engage thoroughly” with the complaints process.

The investigation into Mr Raab is the latest scandal to engulf a senior member of Mr Sunak's government.

Cabinet member Gavin Williamson was forced to resign earlier this month after he too faced bullying claims.

Mr Williamson reportedly sent abusive text messages to the party’s former chief whip, Wendy Morton, complaining that he and others had been excluded from Queen Elizabeth II’s funeral for political reasons.

In the messages, Mr Williamson reportedly started by saying: “There is a price for everything”. He said Ms Morton's conduct was “absolutely disgusting” and went on to use multiple expletives.

He is facing an investigation over the messages.

Mr Sunak promised to serve with “integrity and humility” when he succeeded Liz Truss in late October.

But within days of taking office, he was facing criticism for bringing Suella Braverman back into government, six days after she was found to have breached the ministerial code, forcing her resignation under former prime minister Liz Truss.