Supposing that it was an isolated 'the skies go dark' scenario, then being self-sufficient in food is quite a complex question to try to answer, as most food chains require the skies to not be dark, at least not all the time.
An interesting (and today, happily, academic) question is what happens to the UK in the event of, say, AMOC (Atlantic Meridional Overturning Circulation -- aka the gulf stream that sends warm air up from the equator) shutting down. Noting that London's only 4 degrees latitude away from, say, Moscow.
And then it becomes a much more fascinating question.
Oddly, as an exception, the Netherlands would probably go a long way even if the skies went dark, due to the large surface area of artificially lighted and heated greenhouses.
> An interesting (and today, happily, academic) question is what happens to the UK in the event of, say, AMOC (Atlantic Meridional Overturning Circulation -- aka the gulf stream that sends warm air up from the equator) shutting down. Noting that London's only 4 degrees latitude away from, say, Moscow.
Probably not that much because the notion that the gulf stream shutting down would send Northern Europe into an ice age is mostly a fiction:
Simply being next to an ocean with prevailing winds off that ocean is what gives the UK an oceanic climate, if the gulf stream vanishes there might be some slight cooling but it isn't going to make Glasgow have the same climate as Moscow because Glasgow won't be far inside a continental landmass.
Author doesn't mention rainfall impact at all - but my understanding is if AMOC shuts down completely (highly unlikely) UK's arable land drops significantly, because of the reduction in predicted rainfall.
Author also sounds a bit hand-wavey with the claim that '50% of heat comes from east-ward wind patterns, the other 50% comes from stationary waves of atmospheric flow'.
I guess it's feasible that the gulfstream provides zero warmth to the air above it as it flows north and around the UK, but this is a challenging claim.
It's odd the author didn't put in any estimates on temperature change from AMOC shutdown -- elsewhere I'm seeing an expected average delta in the south of perhaps 1 or 2 C, and in the north of Scotland, up to 4C.
I found author's actual paper [1] but that doesn't mention rainfall either, and I can't find any estimated ranges on temperature impacts for the UK.
An interesting (and today, happily, academic) question is what happens to the UK in the event of, say, AMOC (Atlantic Meridional Overturning Circulation -- aka the gulf stream that sends warm air up from the equator) shutting down. Noting that London's only 4 degrees latitude away from, say, Moscow.
And then it becomes a much more fascinating question.