Down there in the aching panic of Portugal, there are many things they do not need. Investigation into the disappearance of Madeleine McCann is not helped by psychics, prurience, false sightings or – at least as distracting from useful effort – by the intrusion of urban myth. And yet, over the past ten days, we have watched it flourish with unedifying ease.

The first mention I heard was on the Today programme, when Kerry Grist was invited to resurrect memories of the disappearance of her 21-month-old son, Ben Needham, 16 years ago on Kos. Still her main suspect, she said, is the huge, organised trade – involving everyone from social workers to (of course) gypsies – wherein children are stolen then sold to the childless. Astonishingly, Today offered no challenge whatsoever to this assertion; not so much as a gentle question.

Within days, this “organised trade” took its place in the wild line-up of theories relevant to Madeleine. Phone-in hosts let it into discourse, again unchallenged, as did tabloid speculation; by the weekend, even The Sunday Times, also revisiting the Needham case, bought it. It stated as fact, that, with special preference for blue-eyed blondes, “Racketeers are known to have abducted toddlers in Greece to sell to wealthy childless couples”. Really? So show me the case studies. OK, just a couple, then. Even just the one . . . anybody?

I have repeatedly asked police and press, British and Greek, for a single example to support this rumour. There is none. When pretty little Western European kiddies go missing, as with Madeleine, we know about it; if we don’t know, it isn’t happening.

It is understandable that Kerry Grist clings to her urban myth, even without a shred of evidence that her son was abducted at all. Those of us who properly investigated Ben’s disappearance are certain he was not; put bluntly, a child less than 2, toddling unsupervised for five hours on a baking, remote, inhospitable hillside that is still largely unsearched, is easy prey to the lonely accident. Nevertheless, to believe in abduction is to allow for the chance he is alive, and who would deny that to Mrs Grist?

For any among the rest of us to accept the myth, without such excuse, is another matter. It points to nothing loftier than xenophobic triumphalism: we have paedophiles, as do “they”; we have desperate, barren madwomen, as do “they” – but at least we don’t have organised bands of evil, swarthy foreigners grabbing our babies to flog in their vile markets. So there.

Our willingness to go along with the nonsense is a distasteful but salient reminder that, European Union notwithstanding, our nation states still don’t much like each other – and it takes just one tragedy, for just one family, to show how damned flimsy is any pretence otherwise.

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