Too interconnected?

In these days we live in a very interconnected way and we take this for granted. 

Electricity in the UK (and many places) comes from gas a great deal still. Most of the UK's food is imported. Most goods are bought with cards. Fuel is imported. Most of out manufactured goods come from abroad. The internet works because it is vastly connected. Most of us depend on our smart phones.

Just imagine if we had a sudden shock and had to live without some (or all) of these. Would society be able to cope?