Tristram Stuart likes to rummage in bins. A tall, 32-year-old with floppy hair and chiselled features, he is a connoisseur of rubbish in all its variety. He can tell you what time central London convenience stores put their binbags out on to the streets and hazard a good guess as to what will be in them. He can tell you about how the waste policies of major supermarkets differ: how much of their rubbish is diverted to landfill and how much is recycled or incinerated; which ones lock up their bins, and which leave them open. Stuart is a “freegan” – someone who subsists largely on food discarded by others. Through this practice, he has become thoroughly acquainted him with the ins and outs of rubbish and he long ago got over any squeamishness about handling it. For him, a bin full of chucked-out food is not an object of physical revulsion. Rather, it’s an opportunity.