Detectives made attempt to bug McCanns' villa

Police tried to bug Kate and Gerry McCann's villa in Portugal in an attempt to implicate them in their daughter Madeleine's disappearance, it emerged today.

Portuguese detectives wanted to listen in on the couple in the weeks before they were made official suspects, or arguidos. They applied for a court order for permission to bug the home the couple were renting but were denied by a local judge.

The application is detailed in 30,000 pages of police files made public in Portugal this week. Portuguese police also requested Mr McCann's credit card details over a six-month period, beginning prior to his daughter's disappearance on 3 May last year from a holiday apartment in Praia da Luz.

According to an email in the files, the Home Office turned down the request because it "appears disproportionate".

The bugging operation centred on a house rented by the couple in the weeks after Madeleine vanished. The McCanns left it in September after being made arguidos, and returned home to Rothley in Leicestershire.

The files also reveal how Portuguese police were warned not to draw any "evidential" conclusion from the reaction of a British "corpse" dog in the apartment from which Madeleine vanished and at the McCanns' hire car.

The reaction of the springer spaniel prompted Portuguese detectives to suspect the couple of involvement in their daughter's disappearance.

But in his report, the dog's handler Martin Grime concludes: "The dog alert indications MUST be corroboratedif to establish their findings as evidence." He said there could have been cross-contamination as a result of "a number of given scenarios".

Lawyers acting for Mrs McCann suggested the dog might have reacted because she had been in contact with corpses through her work as a GP.

The police files also show four families stayed in the apartment from which Madeleine vanished before sniffer dogs were brought in and proper forensic samples taken.

The McCanns' arguido status was lifted last month after authorities announced the case was being shelved.

Meanwhile, the Daily Mirror today published an artist's impression of two adults seen with a girl who resembled Madeleine in a shop in Amsterdam. Shopworker Anna Stam reported the sighting to police and the Portuguese were alerted. The drawings show a darkfeatured man aged 35 to 40 and a woman in her forties with light brown hair.