British police helped the Portuguese authorities “develop evidence” against Madeleine McCann’s parents, according to the latest revelations by WikiLeaks

The website claims that two weeks after Kate and Gerry McCann were formally declared as “arguidos” – people of specific interest to the investigation, or suspects – a meeting took place between the US ambassador, Al Hoffman, and the British ambassador, Alexander Wykeham Ellis.

In a diplomatic cable marked confidential, the US ambassador reported: "Without delving into the details of the case, Ellis admitted that the British police had developed the current evidence against the McCann parents, and he stressed that authorities from both countries were working co-operatively."

The comments attributed to the ambassador throw fresh light on the case built against the McCanns, which was widely believed to have been driven by the Portuguese police, and in particular the extent of the involvement of the British police and authorities.

Led by a unit at Leicestershire police, their main involvement with the inquiry was acting as liaison between their Portuguese counterparts and the McCanns, and gathering evidence of suspected sightings or other allegations that were called in by British residents or citizens living abroad.

However, at least one sniffer dog was used in the investigation and, according to reports, was said to have picked up the scent of a dead body in the apartment.

In November 2007 – two months after the ambassadors’ alleged discussion – Portuguese and British police came face to face for the first time since Madeleine’s disappearance six months earlier from her hotel complex in the Algarve village of Praia da Luz, for three days of talks in Leicester.

In one heated meeting, it is believed that the Portuguese police were furious that DNA tests taken from the McCanns’ hire car and analysed at the Forensic Science Services laboratory near Birmingham, failed to show anything conclusive.

In one of two cables referring to the case, the US ambassador wrote: "Madeleine McCann's disappearance in the south of Portugal in May 2007 has generated international media attention with controversy surrounding the Portuguese-led police investigation and the actions of Madeleine's parents."

He reported that his British counterpart thought "that the media frenzy was to be expected and was acceptable as long as government officials keep their comments behind closed doors".

It was not until 21 July 2008 that the Portuguese authorities shelved their investigation and lifted the McCann’s arguido status.

Yesterday a spokesman for the McCanns said: "This is an entirely historic note that is more than three years old. Subsequently, Kate and Gerry had their arguido status lifted, with the Portuguese authorities making it perfectly clear that there was absolutely no evidence to implicate them in Madeleine's disappearance whatsoever.

"To this day, they continue to work tirelessly on the search for their daughter, co-operating when appropriate with both the Portuguese and British authorities."

A spokesman for Leicestershire police said that their involvement in the investigation was limited to coordinating UK-based inquiries on behalf of the Portuguese authorities