Mercedes boss Toto Wolff has challenged Formula One and its governing body to demand greater transparency from Red Bull’s investigation into Christian Horner.

Horner has been cleared to continue as Red Bull team principal following an internal probe into “inappropriate behaviour” towards a female colleague.

Horner was on the Red Bull pit wall on Thursday for both practice sessions of the new season.

“I am pleased that the process is over and I cannot comment about it,” he told Sky Sports. “I am focused on the season ahead. Within the team it (the unity) has never been stronger.”

Red Bull Racing’s parent company, Red Bull GmbH, said it was confident the investigation into Horner had been “fair, rigorous and impartial” but added that the report – understood to stretch to 150 pages – is “confidential”.

It is understood that neither Formula One’s owners, Liberty Media, nor its regulator, the FIA, has seen the report.

However, there were growing calls in Bahrain on Thursday night for Red Bull GmbH to share the details of their investigation.

“I just read the statement, which was pretty basic,” said Wolff. “My personal opinion is we can’t really look behind the curtain.

“There is a lady in an organisation that has spoken to HR and said there was an issue and it was investigated and yesterday the sport has received the message that it’s all fine, we’ve looked at it.

“I believe with the aspiration as a global sport, on such critical topics, it needs more transparency and I wonder what the sport’s position is?

“We’re competitors, we’re a team and we can have our own personal opinions or not. But it’s more like a general reaction or action that we as a sport need to assess, what is right in that situation and what is wrong.

“Are we talking with the right moral approach, with the values based on the speculation that is out there?

“As a sport, we cannot afford to leave things in the vague and in the opaque on critical topics like this, because this is going to catch us out.”

McLaren CEO Zak Brown agreed with his Mercedes counterpart.

“It’s the responsibility ultimately of the organisers of Formula One, the owners of Formula One, to make sure that all the racing teams and the personnel and the drivers and everyone else involved in the sport are operating in a manner in which we all live by,” said the American.

“I don’t think it’s the teams’ roles and responsibilities. That’s up to FIA and Formula One to ultimately decide and ask what they feel gives them the level of transparency they need to ultimately come to their conclusion and we just have to count on them that they fulfil that obligation to all of us.”

The PA news agency has contacted Formula One and the FIA for comment.

Horner, who has protested his innocence throughout, was questioned by a lawyer for eight hours earlier this month at a secret London location.

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

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 Dutch driver Max Verstappen setting a new record for 10 consecutive victories as he wrapped up his third title.

Horner, who is married to former Spice Girls singer Geri Halliwell, was awarded a CBE for his services to motorsport in the New Year Honours.

Christian Horner wants his Red Bull future to be resolved “as soon as possible” as the embattled team principal fights to save his Formula One career.

Red Bull Racing’s parent company Red Bull GmbH announced on February 5 that Horner is being investigated following an accusation of “inappropriate behaviour” by a female colleague. Horner denies the claim.

Horner addressed the media alongside four other F1 team principals on the second day of this week’s three-day test in Bahrain on Thursday. The new season starts in the Gulf kingdom next Saturday.

Asked why he has not moved aside as team principal and chief executive of Red Bull Racing with the investigation under way, Horner replied: “As you are well aware there is a process going on which I form part of, and as I form part of that process, I am afraid I cannot comment on it.”

Horner was then asked if he could provided a timeline as to when the investigation might be over.

The 50-year-old added: “I am dreadfully sorry but I really can’t comment on the process or the timescale.

“Everybody would like a conclusion as soon as possible. But I am really not at liberty to comment about the process.”

Sources have indicated to the PA news agency that there could be a resolution before the opening race on March 2.

On Wednesday, Mercedes boss Toto Wolff called for Red Bull’s probe to be transparent, and said the controversy is “an issue for all of Formula One”.

McLaren chief executive Zak Brown, speaking in the same press conference as Horner on Thursday, echoed Wolff’s comments.

“The allegations are extremely serious,” said Brown. “McLaren hold themselves to the highest standards of diversity, equality and inclusion.

“These are extremely important to us and our partners, and to everyone in Formula One.

“Red Bull Corporation has launched an investigation, and all we hope and assume is that it will be handled in a very transparent way, and as the FIA and Formula One has said, swiftly, because these are not the headlines that Formula One wants or needs at this time.”

Red Bull won all but one of the 22 races last year as Max Verstappen stormed to the world championship.

The Dutch driver, in his heavily upgraded machine, set an impressive pace on the opening day in Bahrain, finishing 1.1 seconds clear of anyone else.

Mercedes’ George Russell said: “Red Bull are definitely the favourites and definitely a step ahead of everyone here in Bahrain. They have had an impressive winter, no doubt.

“Hopefully Red Bull are already in that sweet spot, and we can close the gap, but it is going to take a lot of hard work to do so.”