Natalie Haynes: The Essex lion is ludicrous, but that doesn't stop us wanting it to be true

London Zoo is currently refurbishing a large area that backs on to Regent's Park. Where once there were camels and a pigmy hippo, now there are diggers. Recently, a sign was added, explaining that they were building the new tiger enclosure there. "Ooh, tigers next to the park," I thought, as I strode past on my way to work. Then, a moment later, "Wait, tigers next to the park?"

Luckily, we've never had to deal with anything more alarming than a red panda escaping from London Zoo, which clearly locks up its big cats with care. As does Colchester Zoo, for the Essex lion has, like every other big cat on the loose, disappeared as completely as the Loch Ness Monster and the Beast of Bodmin Moor. He is probably a Maine Coon cat which lives nearby. So the magical thought of Aslan wandering Essex in search of a woman with a hefty supply of Turkish delight is gone, too.

Escaped big cats are the urban myth of the countryside: the tales abound because so many of us want them to be true. It's always big cats caught in a blurry photograph, never zebras or wolves or bears, which are surely just as likely to have escaped from a private zoo as a lion. Even now, with the search called off for lack of evidence, one newspaper poll suggests that more than a third of us think the Essex lion is real.

The desire to believe something which is manifestly false is extremely powerful. The brilliant documentary, The Imposter, out last Friday, illustrates this beautifully: it tells the story of a blond, blue-eyed boy who disappeared in Texas aged 14. Three years later, a dark-haired, brown-eyed man in Spain claimed to be the missing child. I won't spoil it for you, only urge you to go and see what people are capable of believing when they want it to be true.

I suspect the same tendency is at work with the current spate of Twitter deaths: our craving for a good story trumps our need for evidence. Margaret Thatcher's death has been reported as fact online plenty of times, though it hasn't yet proved true. But the rumour spills over into the real world nonetheless: I saw a comedian in Edinburgh do a good five minutes about her death a few weeks ago, because he'd read about it just before coming on stage.

Even Russell Brand has had to debunk rumours of his death this week. One documentary about addiction, and he's shunted towards the great beyond. It seems our love of a good story requires a big finale. But reports of his death, much like the life of the Essex lion, are exaggerated.

Come on in. The vegetables are lovely

Over the next 40 years, scientists have warned that food shortages might lead to more of you coming round to my way of thinking, and going vegetarian. Well, you might not come round to it, exactly. Some of you will probably be dragged there, offering your first-born child in exchange for just one more forkful of steak.

But the good news is that it has never been easier to be vegetarian. When I turned to the ways of leafiness, 24 years ago, it was rubbish. For a start, I was a teenager, so I didn't really like vegetables. Soya mince came in a dry bag, like fat dust: it had to be hydrated (and heavily salinated) to taste of anything at all. And pre-BSE, there were virtually no vegetarian sweets.

But now I have come to see that pretty much all vegetables are delicious (not mushrooms, obviously. But then, they aren't a vegetable). Fake sausages are often made of potatoes and peas, which means you can have, in essence, mash and mash for dinner, which is what I always secretly wanted. And as for the sweets, M&S now makes vegetarian Percy Pigs. You can get vegan marshmallows delivered to your house. I only await the vegetarian fruit pastille for my life to be complete.