A pandemic isn't a completely unknown situation, unless the goverment is incompetent and doesn't plan properly.
If governments in general (not just the UK) undertook adequate scenario planning studies and acted on their findings, they would be in a much better position to respond.
If you scenario plan for a number of different situation's happening (from best to worst outcome), it allows you to map out a potential response well in advance, in a calm and measured way.
Then if any particular scenario actually happens, you then have a road map, which allows you to follow in a crisis, rather than blind panic.
Businesses use this and Shell developed a very detailled scenario planning method, which is used to develop Corporate Strategy.
To say something along the lines of this being completely unprecedented and completely unknown isn't accurate (because pandemics can and do happen - Spanish Flu 1918, SARS, Swine Flu, etc) and secondly because it gives the government a free pass, to not bother planning properly.
The UK has clearly made some major mistakes specifically regarding lack of 'track and trace', lack of PPE for front line NHS and care workers and insufficient test kits and ventilators. They have done some things very well, like the Nightingale hospitals and economic packages they've provided.
We've now got the highest death rates in Europe, ahead of Italy and an open inquiry is urgently needed after the event.
This isn't about partisan politics, it's about competence and learning lessons from past mistakes. Our government has clearly made some big errors.