The FIA announced on Thursday that it had dropped an investigation into the F1 Academy managing director and her husband, Mercedes boss Toto Wolff, over an alleged breach of confidentiality, after finding Formula 1's compliance rules to be sufficiently robust to prevent any breaches of confidentiality.

The move came 48 hours after the FIA announced its compliance department was looking into allegations against the Wolffs, and 24 hours after Mercedes' nine rival teams united in coordinated social media posts to deny making any complaints about them.

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Seven-time world champion Hamilton, who drives for Mercedes, criticised the FIA while speaking in a press conference at the organisation's end-of-season prize-giving ceremony in Azerbaijan on Friday.

"It has been a challenging week, I think," Hamilton said.

"A disappointing week really to see that the governing body of our sport has sought to question the integrity of one of the most incredible female leaders we've ever had in our sport, with Susie Wolff, without questioning, without any evidence.

"And then just saying sorry at the end, and that's just unacceptable."

Hamilton was speaking just a few hours after Susie Wolff had released a statement criticising the FIA and promising "to follow up until I have found out who has instigated this campaign and misled the media."

Toto Wolff, meanwhile, said on Friday that he would not be "commenting officially for now" as Mercedes are in "active legal exchange with the FIA" regarding the situation.

"We've got a lot of great people within the sport that are doing amazing work," Hamilton continued.

"There is a constant fight to really improve diversity and inclusion within the industry, but it seems that there are certain individuals in the leadership within the FIA that, every time we try to make a step forward, they try to pull us back, and that has to change.

"This is a global sport and we have such an incredible opportunity and actual responsibility to be leaders of change. As we're travelling to all those countries around the world, we have a responsibility to make sure that we're pushing in the right direction.

"I do want to acknowledge that there are a lot of people that are doing great work, but we need to make some changes to make sure that we are all pushing in the right direction."

Mercedes and Formula 1, who Wolff works for in her capacity as the managing director of the all-female F1 Academy series, had reacted angrily on Tuesday night to what they described as baseless allegations against the pair and the fact the FIA had not notified them of the investigation prior to releasing a statement to the media.

Wolff, the last woman to drive in an F1 practice session, had said, before the FIA dropped the investigation, that she was "deeply insulted but sadly unsurprised" by the unsubstantiated claims that seemed "to be rooted in intimidatory and misogynistic behaviour" which was "focused on my marital status rather than my abilities".

The FIA said it was following due process in the wake of a competitor's raised concern. The governing body also rejected any notion that its investigation was prompted by misogyny.

FIA president Ben Sulayem hospitalised after fall and concussion

The implications of the episode, and the nature in which it developed, appear set to be felt longer-term amid continued focus on the relationship between the FIA and Liberty Media-owned F1, the commercial rights holders of the sport.

While the only official comment that has come from the FIA to this point has been its two statements, the ongoing situation has added intrigue to FIA president Mohammed Ben Sualyem's expected appearance in Baku on Friday.

However, the FIA announced on Friday that Ben Sulayem would play a reduced role in the ceremony following a recent fall, which resulted in concussion and time in hospital.

An FIA spokesperson said: "Several days ago the President [Mohammed Ben Sulayem] took ill and suffered a fall and concussion. He received care in hospital and will make a full recovery."

Ben Sulayem had previously posted a video of himself on social media on Wednesday at the opening day of FIA General Assemblies in Baku, in which he appeared to be in good health.

"Great first day of the 2023 FIA General Assemblies in Baku, leading global conversations towards a brighter future for mobility and motorsport," he wrote in the post, from which the video has now been deleted.

Watch our 2023 Season Review live on Sky Sports F1 at 7:30pm on Friday, featuring exclusive interviews with Red Bull team principal Christian Horner and Mercedes technical director James Allison. Stream F1 on Sky Sports with NOW