The answer seems to be: Norway
Bård Wormdal is the authorative reseacher on the collaboration between US and Norwegian intelligence agencies.
This year he received the Norwegian Press Association's Transparency Award.
Wormdal has worked as a journalist for 35 years with NRK (the Norwegian state's broadcaster).
He has largely been ignored by Norwegian media, and received the award for his three books:
• Spionkrigen - det hemmelige spionsamarbeidet mellom Norge og USA (The Spy War - the secret spy collaboration between Norway and the USA)
• The Satellite War
• Stalking the Bear
The Norwegian intelligence services disliked Spionkrigen and asked him not to publish it.
In this book he quotes former high level operatives in the Norwegian intelligence services who claim that Norway is the United States most important partner in this domain.
Based on his research, there seems to be almost no Norwegian political oversight as to what our intelligence services are doing, and most of our intelligence service's budget has been, possible still is, financed by US intelligence services.
The jury who gave him the reward said:
"Through his books, he has challenged official accounts. He has created space for a broader discussion about Norway's role in international intelligence and our cooperation with the USA."
The jury also believes that Wormdal's work has contributed to the public receiving information and the opportunity to assess and discuss security policy issues on a more informed basis.
IMO - the close cooperation on intelligence service is part of the puzzle that helps explain why Norwegian schools and media gaslight my people on historical and political matters, creating a society where independent and critical thinking isn't highly regarded, leaving us with a very narrow Overton window (what is accepted to discuss, which arguments that can be used.)
NRK gave Wormdal a voluntary redundancy package in 2023.
Buy his books and help spreading the word about his work.
Unknowable, though I am sure that the USA tells Norway and many other countries that they are their most important intelligence partner.