Yes, officially since 1946. https://en.wikipedia.org/wiki/Five_Eyes https://en.wikipedia.org/wiki/Five_Eyes (look also for Nine and Fourteen Eyes on this page)

Yes, officially since 1946. https://en.wikipedia.org/wiki/Five_Eyes https://en.wikipedia.org/wiki/Five_Eyes (look also for Nine and Fourteen Eyes on this page) https://en.wikipedia.org/wiki/UKUSA_Agreement https://en.wikipedia.org/wiki/UKUSA_Agreement