On Monday night, an ally of Mr Johnson’s claimed that Ms Ghani “just wasn’t up to the job” of being a junior transport minister and “wouldn’t have gone if she was vaguely competent”.

Mr Javid quit as Chancellor in the same reshuffle in which Ms Ghani was sacked. He protested moves by Dominic Cummings, the Prime Minister’s chief aide at the time, to make him sack his team of advisers. Last June, Mr Javid was reappointed to the Cabinet to become Health Secretary.

On Sunday, he became the second Cabinet minister to publicly voice his support for Ms Ghani and demand a “proper” probe into her allegations. He described her on social media as “a friend and a credit to the Conservative Party”.

His intervention came after Nadhim Zahawi, the Education Secretary, also backed her, tweeting that she was “a friend, a colleague & a brilliant parliamentarian”. He added: “This has to be investigated properly & racism routed [sic] out. #standwithNus”.

The Telegraph approached Ms Ghani and Mr Javid for comment.