I don't think that Gordon Brown's advice to people to make better use of leftovers will go down very well. It smacks of the nanny state at its worst and many people will feel that the blame for food inflation is being shifted on to them.
There is a tremendous amount of waste in the food chain. A lot of it occurs when supermarkets reject produce that does not meet their exacting quality standards, although Waitrose started an interesting 'ugly fruit' initiative not so long ago.
Much of the waste that does occur in the home is through people throwing food away before it is eaten rather than cleaning up their plates. The fact that food is past its 'sell by' date does not mean that it is unsafe to eat. It is as much to protect supermarkets against litigation as anything. However, our youngest daughter regularly throws out anything past its sell by date she finds in our fridge and no doubt does the same in her own household.