Officers from a specialist Spanish unit are making inquiries in Nerja after a tip-off from colleagues in Portugal ten days ago.

The information was sent in an email to a new team of detectives in Porto who have re-opened the case.

Yesterday sources close to Maddie’s parents Kate and Gerry said they were following developments closely.

They added the pair had no plans to travel to Spain until investigators had examined the information further.

Officials in Nerja — close to holiday hotspot Malaga — called on witnesses to come forward last night.

Town hall spokesman Antonio Gallardo said: “We haven’t been informed by anyone officially about this sighting.”

The team in Porto is trawling thousands of pages of case files. They are said to have received the new information from an informant. The McCanns’ Portuguese lawyer Rogerio Alves called the review a “very positive sign”.

Madeleine disappeared in May 2007 from the Algarve resort of Praia da Luz when she was three.

The latest information was passed to Spain’s Judicial Police’s Central Specialised and Violent Crime Unit, which deals with missing persons. Its officers are already probing two siblings who vanished in Cordoba last October. Their dad has been arrested.

t.wells@the-sun.co.uk