so what would you have done if there had been no IMCR in the first place just like the rest of the world?
For the answer to that one, get in your plane, leave UK airspace, and fly on for say 1000nm in any random direction, while counting the GA planes which you hear on the radio. Don't bother to spot any (there usually won't be any to spot).
That's the choice. A lot of problems are solved by altogether eliminating the subject matter.