For reference:
https://www.coe.int/en/web/conventions/full-list?module=treaty-detail&treatynum=205
The UK was active in negotiating the Tromsø Convention and worked to ensure that it did not go above the standard of the UK’s FOI law. The Convention’s drafters were also anxious to ensure it was capable of being accepted by the greatest number of Council of Europe member states, 40 out of 47 of which already had access to FOI legislation by 2009.
When the Convention came into effect the UK Government (New Labour - Gordon Brown) stated that it did not intend to sign the Convention for the foreseeable future and an official statement from the Ministry of Justice observed that “The UK's Freedom of Information legislation has been a success story, providing a regime for freedom of information that is among the most open and rigorous in the world. It already goes further than the standards of the Convention in a number of areas.”
Meanwhile, here is Tony Blair's thoughts on FOIA 2000
https://www.bbc.co.uk/blogs/opensecrets/2010/09/why_tony_blair_thinks_he_was_a.html