"The UK fails horribly on economic, ecosystem and energy... they're toast."

I have to disagree a little here. The UK is getting more and more integrated with Europe at the economic level every year. And Europe while not exactly booming over the last 3-5 years has also been making much more effetive use of it's advances. More public transport, more alternative energy, Less debt (excluding Britain and Spain) at the personal level.

Also the UK has only just started importing Oil and Gas. The US can't say that they are still 90% domestic for their Oil but the UK can (mind you it will be dropping quicker). Cut off British oil imports and prices of petrol would spike causing a shift of travel to the public tansport infrastructure. Cut off US imports and people start to starve, no public transport to fall back on and people have to travel just to get to food (you could limit use to food distribution, and the military/emergency services, but people may still need to travel 10 mile round trips for food in desert climates).

I suspect no country will handle the situation well but I disagree with the UK failing horribly in the short to mid term (2-5 years).