Christian Horner’s future in Formula One hangs in the balance as the Red Bull team principal prepares for a crunch meeting on Friday where he must defend himself against allegations of inappropriate behaviour that might end his career.

On Friday at an undisclosed location believed to be in central London, Horner will sit down with an English KC, appointed by Red Bull Racing’s parent company, the drinks manufacturer Red Bull GmbH, and face questioning on the allegations made by a female employee that he used what is understood to have been described as “controlling” behaviour in his interactions with her.

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The employee is believed to have already presented her evidence, which includes physical documentation, to the barrister and Horner now must make his case to save his job and his career. He has taken legal representation and intends to defend himself robustly.

Horner has already emphatically denied any wrongdoing but must now provide substantive arguments to verify his claim. It will be as intense and as crucial a moment as he has faced in 20 years in F1.

The 50-year-old is the longest serving team principal currently working in the sport, having been taken on by Red Bull when the team entered the sport in 2005. He is also, alongside Mercedes’ Toto Wolff, one of the two most successful principals of the modern era. Whether there are further achievements ahead and the nature of the legacy he leaves will now depend on what he can present to the barrister heading the inquiry on Friday.

Related: How Christian Horner has thrived in the high-octane sphere of an F1 team

Since the news broke that Horner was under investigation it has dominated F1, far overshadowing this week’s series of car launches for the 2024 season. It took Horner as much by surprise as the rest of the paddock when Red Bull Racing’s parent company announced on Monday it had opened an investigation into the team principal and was unequivocal that it had every intent to deal with the matter properly.

“After being made aware of certain recent allegations, the company launched an independent investigation,” it said in a statement. “This process, which is already under way, is being carried out by an external specialist barrister. The company takes these matters extremely seriously and the investigation will be completed as soon as practically possible. It would not be appropriate to comment further at this time.”

The female employee has not been named nor any details of her complaint made public, other than that the behaviour in question was “controlling” in nature, indicating it was likely an employee with whom Horner must have had personal interaction. Red Bull Racing have made no formal comment since the announcement and Horner too has not commented beyond the statement that “I completely deny these claims” he made on Monday.

Red Bull are set to launch their 2024 car on Thursday of next week and the hope within the team is that the matter is resolved before then. It is understood no decision will be announced immediately after the meeting but that the KC will consider the evidence of their inquiry over the weekend before delivering his conclusions to Red Bull.

Rumour and conjecture have surrounded the case since it began, amplified by the lack of comment and information coming from either Red Bull Racing or the parent company while the investigation is under way.

However supporters of Horner have indicated that he has been left shocked and disturbed by what they believe to have been a power struggle over the team that lies behind the investigation. They consider it an attack from Austria by the parent company, with one source describing it as an effort to “clip his wings or remove him from the job altogether”.

Horner’s allies argue that the inappropriate behaviour defined as “controlling” in nature was not aggressive or bullying and that perception of his actions will be key in making his case.

The 50-year-old occupies an unusual position in F1 in that he is not only the team principal of Red Bull Racing but also the CEO of all three of its arms: Red Bull Racing, Red Bull Powertrains and Red Bull Advanced Technologies. He controls the business side as well as the sporting operation.

Before the death of the founder of Red Bull, Dietrich Mateschitz, in October of 2022 the owner was happy to leave Horner running the entire show. This is believed to have changed with the appointment of Oliver Mintzlaff as managing director. Mintzlaff is reportedly being considered as a potential replacement for Horner.

Supporters argue that the motivation behind the parent company’s handling of the situation is an attempt to destabilise Horner in order to potentially remove him. Red Bull GmbH have yet to comment on this interpretation.

Horner has reigned over a period of extraordinary success for Red Bull racing as they have won six constructors’ world championships and seven drivers’ titles. They have dominated the past two seasons with an exceptional car and driver, in the form of Max Verstappen, buta sudden change of management or of team principal would leave the team reeling with the new season set to begin in Bahrain on 2 March.