Thinking about it from where I am right now, I don't think it is crazy.
Let's think about it again: China, Japan, South Korea, Hong Kong and Taiwan. They are countries which are very connected to each other; and yet, somehow, they managed to contain it. It's 'herd responsibility'. The people are applying social distancing and hygiene rules, that's why it's working.
It's possible, as a knowledgeable politician, that you recognize that it's impossible to implement such measures in your country. The reasons are beside the technical abilities of your government: Your citizen are not committed enough to the hygiene. And that's not because Asians are cleaner or superior, they have been exposed to these viruses before and thus they are already trained to deal with them.
It's not the same deal for many countries of the west. We didn't have much trouble in the last few decades and thus people have forgotten why we do most of the hygiene measures in the first place.
Also, here is my first reaction, as a citizen, if the government has declared 'herd immunity' as their strategy: STAY AT HOME. I'd also probably warn the closer one and avoid contact with them too.
So the UK might win twice here: Have enough social distancing by fear (and fear is a hell of a thing as you experienced in the last few days); and also have its population adopt strict hygiene and distancing rules making it safer in the future and readier for the next disease.