Standing under the pine trees in a busy Spanish campsite yesterday morning it was hard to see how anyone could hide a secret there, let alone a secret as big as Madeleine McCann. It's so close to the fast road that follows the Costa Del Sol you can hear the traffic. Grandmothers shuffled past with their wash bags looking straight into the camera. Mums hustled kids away. And eventually security kicked me out. There are even gaps above and below the toilet and shower cubicles for goodness sake. No kind of privacy at all. If you've ever been camping in the Med you know the score. Remote it is not.

So why would Madeleine's abductors have exposed themselves by taking her here after stealing her so expertly in the night.

That is what police will be wondering as they probe a credible sighting of Madeleine that has only just emerged. It places her at this most unlikely of places just three days after she disappeared.

A woman has come forward claiming to have seen a girl who looked like Madeleine with a German family under very suspicious circumstances. First, the witness said, the girl was groggy and looked nothing like the other children in the family. Second, the family added an extra child to their booking the day they arrived. Third, the car they were driving had false plates. The registration number didn't match the age of the car.

So why has this only just emerged? Well the McCanns are being careful what they say here. It's thought the witness reported this to Portuguese police at the time, which makes it, technically, a very old lead. But as we know that investigation went nowhere. Many leads went unchecked. I understand that just last week the witness restated her claims in Spain. They came to the McCann's attention for the first time. And the McCanns notified the British Police team reviewing the case.

That team now has a car to trace and a name to follow up thanks to the campsite log book.

Meanwhile Madeleine McCanns birthday is on Saturday. Once again her parents will have to mark a day that presents them with a awful question. 'Is' Madeleine nine years old today or 'would she have been'. I had a hint of how difficult this day is for them last year. That's when I first met Kate and Gerry. When I clumsily muttered something about "this difficult day" she looked like she had just been stabbed. She actually flinched. And it still haunts me.

So as unlikely a place as the campsite may seem, let it be investigated. And here's hoping it is finally the needle in the haystack that points them to their little girl.

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