Re: Well that's weird....
Hello Justthefacts, weird you didn't do some more "fact cheking". And who is this "the EU claims" chap, any link to him you could provide.
There is more or less what you need on the Wiki: https://en.wikipedia.org/wiki/European_Space_Agency
"EU and the European Space Agency
The political perspective of the European Union (EU) was to make ESA an agency of the EU by 2014, although this date was not met. The EU is already the largest single donor to ESA's budget and non-ESA EU states are observers at ESA".
Since 1 January 1979, Canada has had the special status of a Cooperating State within ESA. By virtue of this accord, the Canadian Space Agency takes part in ESA's deliberative bodies and decision-making and also in ESA's programmes and activities. Canadian firms can bid for and receive contracts to work on programmes. The accord has a provision ensuring a fair industrial return to Canada. The most recent Cooperation Agreement was signed on 2010-12-15 with a term extending to 2020. For 2014, Canada's annual assessed contribution to the ESA general budget was €6,059,449 (CAD$8,559,050). For 2017, Canada has increased its annual contribution to €21,600,000 (CAD$30,000,000).".
I would assume the UK will eventually apply for something similar.
And there is of course https://www.esa.int/ESA
I would suggest you read before you write, I have found it very useful to do it, and at times I have not, which has annoyed me a lot.