Christian Horner continues to fight for his Formula One career following a string of allegations against the Red Bull team principal.

Here, the PA news agency looks at the key questions surrounding Horner, Red Bull, and the sport.

What were the accusations against Horner?

On February 5, Red Bull Racing’s parent company GmbH confirmed Horner was under investigation following an accusation of “inappropriate behaviour”. The company said it “takes these matters extremely seriously and the investigation will be completed as soon as practically possible”.

Horner denied the claim – made by a female colleague – and remained as team principal and CEO of the Milton Keynes-based team. It is understood the complainant also continued in her role.

How did Red Bull react?

Horner was questioned by a lawyer for eight hours at a secret London location. There was no immediate resolution and Horner subsequently appeared at Red Bull’s car launch on February 15.

He continued to dismiss the allegations. Horner then headed to Bahrain for last week’s three-day test before returning to England, while Red Bull’s Austrian board met to discuss his future.

What was the verdict?

On the eve of this weekend’s curtain raiser – and 23 days after it emerged Horner was under investigation – Red Bull GmBH said the grievance against the 50-year old had been dismissed.

The corporation said it was confident the investigation had been “fair, rigorous and impartial” but added that the report, understood to stretch to 150 pages, is “confidential”. However, a number of senior figures in the sport felt Red Bull’s probe lacked transparency.

So, what happened next?

Twenty-four hours later, a number of messages and images apparently exchanged between Horner and the complainant were sent from an anonymous email account to 149 members of the F1 paddock – including FIA president Mohammed ben Sulayem, F1 chief executive Stefano Domenicali and the grid’s nine other team principals, as well as members of the media.

What did Horner say?

Horner released a statement saying: “I will not comment on anonymous speculation, but to reiterate I have always denied the allegations.”

He was back in the paddock a day later for qualifying as Max Verstappen took pole position. There was speculation that another damning email leak against Horner would arrive on Friday – but it failed to materialise.

Will the FIA take any action?

It is understood the FIA explored bringing a disrepute charge against Horner – and assessed the legalities of seeking Red Bull to hand over its report – but no action has emerged.

Neither F1, nor its regulator, has commented publicly on the latest allegations. Horner met with both Domenicali and Ben Sulayem on Friday.

And what about Red Bull’s sponsors and partners?

There is thought to be considerable unrest and unease behind the scenes following the latest allegations to hit Horner – but there has been no public comment from Red Bull Racing’s two biggest partners – Ford and Oracle.

Will Horner be on the pit wall for Saturday’s race?

Yes. It is understood Horner remains defiant that he can see out the controversy.

His wife Geri Halliwell flew to Bahrain and could be trackside on Saturday, while Chalerm Yoovidhya, who owns 51 per cent of the Red Bull group, might also be in attendance.