London is preparing to be overrun by Olympic tourists – or possibly exactly the opposite.

Apparently, so many of us are planning to go abroad, London could be in as much danger of tumbleweed as traffic jams. Quoting the oracle that is AOL Travel, Alamo car rental says that one in five Britons is planning to go abroad during the Olympics. Coincidentally, BBC Radio 4 carried a story yesterday, saying that hotel bookings are down in London this summer compared to last year.

We consulted an Athenian who experienced the Greek Olympics in 2004. She expressed amazement that this myth continues to circulate (and they know a thing or two about myths). Exactly the same predictions were made about millions of foreign tourists clogging up Athens during the Games and she said it just never happened.

The line from Alamo is that Brits need to book early to be sure of a car rental abroad this summer, but that sounds a bit like the Olympic myth in reverse. We can't quite imagine the car rental desk in every Mediterranean resort saying, "Sorry, we've got no more cars – it's all those refugees from London wot done it."