For those of us with small (or even those without!) gardens can I suggest your having a go at growing some food. Try growing now even if you intend to BUG out - it will be invaluable experience.
We grow most of our veg this way - until a couple of years ago I didn't think it was financially 'worth it' but with the recent food price inflation, growing your own food is viable. And believe you me, your own home grown veg. tastes so much better than anything you can buy. And from an environmental perspective it's good to measure you food consumption in 'food yards' rather than 'food miles'!
The secret, for growing with minimal land, is to use containers and/or fertiliser sacks. Containers could be anything from old broken buckets to largish flower pots. If you line a bucket with a plastic sack (has to be stronger than a bin liner) you can uncrease the yield by adding soil as the crop grows. I'll explain:
Potatoes are a great start. If you can get hold of a fertiliser sack for free great but a rubble sack will do - most sacks will not be waterproof, if yours is (or you are using a bucket or suchlike) then make a few holes for drainage to prevent the soil becoming waterlogged. Six inches of soil mixed with compost, pop a chitted potato or 2 on top(chit pointing up), add another 2 inches of soil/compost. Fold down the sack to maximise the light that gets to the soil. After a few weeks the chitted potato will have sprouted. When it is a few inches high add more soil/compost and repeat until the sack is full. Remember to water the sack if necessary! You will get better yields with suitable fertiliser. After say 3 months or so the plant will eventually start to die back, this is the time to lift the spuds. Last year we actually got 5kg of spuds from 1 sack (this was an exceptional yield).
Other good crops to grow, using this method include leeks (pick throughout the winter).
Try some container gardening for herbs as well
If you have a go you will learn
Edited @ 12.20:
Wilko's are a good source for seed potatoes etc. If you have an Aldi near you they are having some 'deals' from this Thursday. http://www.aldi.co.uk/uk/html/offers/of ... sday12.htm
(seed potatoes as well as veg. seeds collapsable greenhouse etc)