If you have a diesel car and fuel becomes unobtainable/stupidly expensive, you could run it on chip pan oil. A mate of mine did that, got his oil from takeaways I believe.
It is likely though that said takeaways will see the value of their biodiesel and start asking silly money too. In which case I predict panic buying of Spry Crisp'n'Dry at the supermarkets. Uncertain times ahead :(

