BORIS Johnson is facing the prospect of yet another investigation into his behaviour amid calls for a probe into reports he attempted to gift his wife a plum £100,000 per year job.

The Prime Minister has been accused of attempting to install his then-girlfriend Carrie Johnson as his chief of staff during his time as Foreign Secretary.

The story was first reported in The Times but was dropped from later editions of the paper and the publication’s website after caving to the demands of Downing Street to drop the piece.

The journalist stood by the story, and two sources confirmed to the BBC that Johnson had floated the idea of hiring Carrie, but was advised against it by aides.

READ MORE: Boris Johnson 'suggested COP26 and royal family jobs for wife Carrie'

Now Brendan O’Hara, the SNP’s Cabinet Office spokesperson, has demanded the country’s top civil servant launch an investigation into the Prime Minister’s conduct.

Boris Johnson and Carrie Johnson wait to greet guests for the leaders official welcome and family photo, during the G7 summit in Cornwall

O’Hara has written to Simon Case to urge the head of the civil service to clarify whether the story is “true or not”.

He said the public "deserves answers" over the brewing scandal. 

Simon Walters, the author of the original piece, has said he was never given an on-the-record denial of the story, nor did Downing Street deny it to him off-the-record.

The Prime Minister’s spokesperson has subsequently claimed the story was "not true".

Walters built on a claim featured in Lord Ashcroft’s book First Lady, alleging that Johnson had sought to install Carrie – with whom he was having an affair while still married to his second wife – as his chief of staff but was talked out of it by political allies.

READ MORE: Inside the Tory summer ball where dinner with PM sold for £120,000

O’Hara (below) said: “This is yet another deeply murky story that Boris Johnson finds himself in the middle of, and another report that a Tory minister offered a cushy, tax-payer funded role to their nearest and dearest.

Boris Johnson and Carrie Johnson wait to greet guests for the leaders official welcome and family photo, during the G7 summit in Cornwall

“Given the stench of cronyism surrounding the Tories at Westminster, and the multiple occasions in which Boris Johnson has lied, cheated, wilfully broken the law, and offered senior roles to close allies and friends, it is incumbent on the Cabinet Secretary to take this latest allegation seriously.

“The public deserves answers over whether Boris Johnson as Foreign Secretary used his position to try to get his girlfriend a £100k job – funded by the taxpayers.

“If there is no truth to the story then why was no denial given at the time and why did the Prime Minister’s office intervene?

"Boris Johnson has shown time and time again that he has no respect for the rules or laws that the rest of us adhere to. The sooner Scotland becomes an independent nation, and rids itself of Boris Johnson and the corrupt, broken, self-serving Westminster system the better.”

The Cabinet Office and Downing Street were approached for comment.