I think a second lockdown is going to be an absolute disaster and could absolutely have been avoided, but if the alternative is the same as / worse than what we saw late March / early April with 900-odd dying a day (or worse) then the government is going to have to do it.
Think a second lockdown leads to a lot more problems than the first though.
I know it seems daft to say, but even things like the weather. We were lucky in the UK to have nice weather in April to June and if you were fortunate to have an outdoor space or able to get out on a walk/bike, it kept a lot of people sane (I feel so sorry for people - like yourself I believe - who lived in major cities, but I'm not a city person as it is).
Switch that to a lockdown for November-December, with the pressures of Christmas (just socially it's a thing isn't it), the strain on families, not being able to get out in dark nights and cold weather. It's a recipe for disaster on a very individual level - mental health, physical health etc if gyms have to close.
That's not even counting the financial implications which then go on to impact a lot more lives.
I guess the initial steps will be curfew on bars/restaurants etc. More limits on numbers mixing in households (then again it's much more dangerous going into asda even with everyone wearing a mask).
They'll do all they can - and I do think rightly so - to avoid that second lockdown. NHS should also be able to handle it. I know there was talk the Nightingale etc had been decommissioned, but I was surprised to learn last week that it's ready and waiting if needed. Hopefully it won't be.