Police have been analysing the image using overlays of hundreds of images of Madeleine supplied by Kate and Gerry.

Advanced facial recognition software and enhancement techniques have been used to sharpen the image.

The digital technique enables images to be enhanced but it also allows the user to apply the same conditions to clearer images of those found on the one they want to enhance. This method is used in satellite imagery to detect changes in military installations and experts say that it is a sure way of matching imagery.

Dozens of images of Madeleine’s face have been overlaid on the one supplied by Spanish tourist Clara Torres, from Albacete. Using the enhancement techniques together with resizing methods and specialist imagery equipment, the image is said to be a perfect match.

The missing girl’s desperate parents called on Interpol to press ahead with an urgent investigation into the photograph.

The McCanns’ official spokesman Clarence Mitchell said: “Gerry and Kate now hope it will be thoroughly analysed and its significance properly assessed.”

Police in North Africa are stepping up their search for Madeleine and house to house inquiries are already underway in Zinat, where the image was originally taken. Kate and Gerry McCann are said to be planning a trip to Morocco in the coming few days in case their child is found.