Christian Horner will make his first public appearance on Thursday since an investigation was launched into an allegation of “inappropriate behaviour” against the Red Bull team principal.

The embattled boss is due to attend the world champions’ car launch at their Milton Keynes headquarters following the accusation by a female colleague which surfaced at the beginning of last week. Horner, 50, categorically denies the claim.

For now, Horner remains in his role as team principal and was present at a behind-closed-doors Red Bull test at Silverstone on Tuesday ahead of the new season which starts in just over a fortnight.

Red Bull will unveil their new car on Thursday and Horner is expected to address the media – although the PA news agency understands legalities around the process mean that questions relating to the internal investigation will be off-limits.

Horner will be at Red Bull's Milton Keynes base for their launch on ThursdayHorner will be at Red Bull’s Milton Keynes base for their launch on Thursday (Bradley Collyer/PA)

Last week, Horner was quizzed by a lawyer for eight hours as part of the probe by Red Bull Racing’s parent company Red Bull GmBH.

There had been a strong desire for Horner’s future to be resolved before Thursday’s launch but sources have indicated that he could face further rounds of questioning as he bids to prove his innocence.

Horner has been Red Bull team principal since they entered F1 19 years ago and is the longest-serving boss on the grid.

During that period he has overseen seven drivers’ world championships and six constructors’ titles. Red Bull have dominated the sport in recent seasons and last year won 21 of the 22 races, with Max Verstappen setting a new record for 10 consecutive victories.