When the Event Horizon Telescope project started in 2009 the UK was still part funding and involved in operation of the James Clerk Maxwell telescope which has been part of the project – then we pulled the plug on funding and walked away in 2015 [ironically the UNESCO International Year of Light which celebrated the achievements of all those who had contributed to our understanding of light – foremost amongst them Maxwell]. I think there may still be a bit of involvement somewhere via UCL, but I’m not sure. But, you are right, sadly we don’t have a place at this particular top table.
john s