Christian Horner and Red Bull have been plunged into a fresh crisis following a dramatic leak of secret evidence from the investigation that cleared him of inappropriate behaviour towards a female colleague.

A cache of material made up predominantly of screengrabs from WhatsApp exchanges between Horner and his accuser, including images, was sent from an anonymous email address to hundreds of journalists who have reported on the case.

The dossier of evidence was also sent to Liberty Media as well as Stefano Domenicali, the Formula One chief executive.

“I won’t comment on anonymous speculation, but to reiterate, I have always denied the allegations,” Horner said in a statement read out to journalists by a team spokesman.

Horner’s rivals call for transparency

The leak came as Horner’s arch-rivals questioned the outcome of the investigation that cleared him amid calls for FIA, the sport’s governing body, to launch its own probe into the affair.

Toto Wolff and Zak Brown, the respective team principals of Mercedes and McLaren, criticised the lack of transparency from Red Bull GmbH, the Austrian parent company of Red Bull Racing F1, following its announcement that a complaint against Horner had been dismissed.

Speaking at a press conference ahead of the first grand prix of the season in Bahrain, Wolff said: “There is a lady in the organisation who indicated that there was a problem, it was investigated and yesterday we all received the message that it was OK. I believe that a major sport needs more transparency on such dangerous topics. I wonder what the position of the leadership is. I don’t think it should remain vague as it is now. We are outsiders and, of course, we don’t know exactly what is going on. But, looking at just a statement, it doesn’t seem to me how things should go in today’s time. Although, in Formula One, we may be in our own bubble and others are satisfied with that.”

Brown said: “There are still many rumours and also many questions. I think those who run this sport have a responsibility towards the entire sport and all our fans, to make it clear that everything has been clear and transparent for them. That they come to the same conclusion as Red Bull and they agree with the outcome. Until then, I think there will continue to be speculation and many unanswered questions about the whole process. That is not healthy for the sport. It is up to the FIA and Formula One whether they can clarify whether they have the clarity that is needed.”

Williams counterpart James Vowles said: “I have a responsibility for Williams, and if anything like that happens here, I would want to make sure we properly investigate it and do a robust process that is clear to the outside world what has happened.

“I trust that Red Bull have done a strong process and we have to in that circumstance.

“But what I want is us as a sport to be proud that we are sitting on a set of foundations that is one of inclusivity, one of openness and transparency and all I ask in that matter is that we make sure we have faith and trust that all of the organisations are working for the same standards.”

Horner: Red Bull have never been stronger

Horner earlier spoke for the first time since being cleared, saying he was “pleased” the case was over. He also declared that unity within the reigning Formula One world champions had “never been stronger”.

That followed the conclusion of a weeks-long investigation commissioned by Red Bull GmbH into a complaint made by a female colleague.

A statement announcing the 50-year-old had been cleared was released at almost the exact moment he touched down in Bahrain at 3.30pm on Wednesday UK time.

“I’m just pleased that the process is over,” Horner told Sky Sports News ahead of free practice on Thursday.

“Obviously, I can’t comment about it, but we are here very much to focus now on the grand prix and the season ahead and trying to defend both of our titles.”

Asked if he thought it was the end of the matter, he added: “Well, I can’t give you any further comment. But the process has been conducted and concluded.”

Horner, who has been in charge of Red Bull since the team’s formation in 2005, was asked if he had any regrets.

“Again, I’m not going to be able to give you, I’m afraid, any further comments on it, but I’m pleased to be here in Bahrain and then with the team focused on the season ahead.”

Asked if the team was unified, he added: “Within the team, it has never been stronger.”