What next for Christian Horner, Red Bull and Formula One?

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.

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.

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.

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.

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