Many things in life are desirable but unachievable. Personally, I would love to play chess as well as Magnus Carlsen but I somehow doubt that is going to happen.

It is a similar story with politicians demanding “exceptional access” to private encrypted communications. It is perfectly understandable why security services desire such powers. In the wake of the murderous attacks in Manchester and London, who would not want to tap the electronic traffic of terrorist suspects?

But governments should be extraordinarily careful before forcing technology companies to comply. At worst, their demand may be unattainable in the messiness of the real world; at best, it could result in enormous cost and complexity. The unintended consequences of such action could also be appalling. Mandating insecurity in technological systems, which run so much of the critical infrastructure of the modern world, is inherently a bad idea.