The Two Pound Tram

Wilfred and Duncan live in a large old house in Sussex, only ever see their parents on Wednesdays, and spend their days catching butterflies and dreaming of adventure. Then their mother elopes and their already distant father becomes hostile. So the brothers pack their camping equipment and run away from home. They already have a plan. They're going to London to buy a tram they have seen in an advertisement, and it costs two pounds...