British police helped develop evidence against Madeleine McCann's parents while they were under investigation by Portuguese authorities, according to a claim published by WikiLeaks.

Britain's ambassador to Portugal reportedly made the claim to an American diplomat two weeks after Portuguese police named Kate and Gerry McCann, of Rothley, as "arguidos", or formal suspects, in their daughter's 2007 disappearance.

The message, contained in a US diplomatic communication, surfaced on the Wikileaks website this week.

It does not specify what evidence British police are alleged to have gathered or whether UK investigators were involved in the decision to formally name the McCanns as suspects.

Also, it does not make clear which police force the document refers to.

The McCanns remained under official suspicion until July 2008, when Portuguese police shelved the investigation into Madeleine's disappearance and lifted the couple's status as arguidos.

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 there was absolutely no evidence to implicate them in Madeleine's disappearance whatsoever."

Leicestershire officers were involved in aspects of the case.

A Leicestershire police spokeswoman said: "The investigation into the disappearance of Madeleine McCann is a Portuguese led one.

"Our role from day one has been to co-ordinate and complete any UK based enquiries."

Madeleine, then three, went missing from an apartment in the Algarve on May 3, 2007.