As I understand it, several agencies were asking the government at a recent meeting to begin talking to the public a bit more about emergency preparedness. There is no conspiracy here, there were even journalists in the meeting (well, at least a woman from Sky News).
To be fair, if you were CO of the Logistics Core in the army, tasked with setting up evacuation centres, it's going to make your job a hell of a lot easier if there is some degree of resilience amongst the population.
I agree with a pp that, to some extent, there is a peculiar British thing going on here. If you look at Sweden during COVID, for example, they didn't lockdown as Swedes had a natural inclination towards personal responsibility (and calm, I remember seeing videos of them sat outside cafes).
Whereas here, several government insiders have since said that lockdowns became inevitable because of the public demand for it. British people wanted to be locked down and subject to strict rules about their movements by the state.
I think there's a lot to unpack here about the British relationship with the welfare state versus that relationship in Nordic countries. But that's probably for another thread.