But the British had to be clever...
1. It has not been tried before; who gambles on an experimental solution with 67M people at stake? (I know: brexiters)...
3. It relies on infection providing immunity from re-infection. We don't even know that yet, or how long immunity lasts.
6. There is no way in the real world that the over-65s *could* be successfully cocooned.
Overall it is like something a fantasist might dream up - like Brexit.