It's a normal day at the green customs channel at Heathrow airport. A random check on a jumpy passenger carrying a camcorder case reveals a deadly cargo.... six live rattlesnakes. Producer Will Aslett , who made this film about the animal quarantine stations near Heathrow's Terminal 4, witnessed the incident - and several more like it. Finches from Senegal, stuffed 150 to a cage the size of a briefcase, and a suspiciously cold bag packed with the thawing carcasses of a hunter's booty, from armadillos to silver foxes, bound for an Italian taxidermist. Last year alone, 12,853 animals, mostly endangered species, were seized. All the animals that arrive at Heathrow, whether smuggled or legally imported, have to go through the quarantine station, Europe's first line of defence against disease. But it's an uphill struggle: five new diseases have entered the UK in the past 18 months and the relaxing of European laws on quarantine is makingtheir work even harder.