Murat's lawyer: 'McCanns should be cursed for leaving Madeleine alone'

And Francisco Pagarete described the couple's private detectives as mercenaries who had persecuted his client.

Mr Murat, 34, was the first official suspect in the police investigation into Madeleine McCann's disappearance.

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Attacking her parents in a Portuguese newspaper, Mr Pagarete said: "What they deserve is for somebody to curse them, to make them pay for having left three children unprotected."

He added that their detectives had broken the law in Portugal by trying to put pressure on witnesses.

"I only lament that there are people funding a couple who abandoned three children and who daily swan around the streets," Mr Pagarete told the Portuguese newspaper 24 Horas.

"On top of it all they have bank accounts which are stuffed full.

"While this is going on my client, his mother and his girlfriend, who have nothing to do with the case, see their names daily dragged through the mud and they are on the verge of bankruptcy."

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The McCanns own a £500,000 home. Mr McCann, 39, earns a reported £75,000 as a heart specialist.

The Find Madeleine fund has raised almost £1.1million, which the couple, who also have twins, have used to fund their campaign and to pay their living costs since May, including two instalments of their mortgage. Their legal costs and spokesman are paid for by benefactors.

Criticising the McCanns' firm of private detectives, the lawyer said: "They are constantly persecuting my client and his girlfriend, who no longer have a private life.

"This is simply unacceptable in a state of democratic rights.

"Leave my client alone. Metodo 3 investigators are mercenaries."

Mr Pagarete also accused the McCanns of hypocrisy, claiming they had lauded the Portuguese police as "the best in the world" until they were named as official suspects in September.

The couple then tried to paint the force as the villains in the case, he claimed.

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Madeleine went missing from the family's holiday apartment in the Algarve days before her fourth birthday, on May 3.

Mr Pagarete has been angered by a series of alleged sightings by witnesses who claim to have seen Mr Murat hanging around the family's apartment, and Michaela Walczuch, his German-born girlfriend, with a girl matching Madeleine after her disappearance.

The sightings are being investigated by Metodo 3. The private detectives are working on the theory that Madeleine was kidnapped to order and handed to a paedophile network who took her to Morocco.

They have been contacted by a Portuguese lorry driver who claims to have seen the child with a woman who looked like Miss Walczuch, 34, on May 5, and by a Spanish tourist who said she was "sure" she had seen Madeleine and Miss Walczuch in a remote Moroccan town on June 15.

Mr Pagarete has always said police knew where Mr Murat, his mother and his girlfriend were on the night Madeleine vanished.

Following the interview, he denied having criticised the McCanns but said he stood by his attack on their detectives.

In August, he said: "Some people in Praia da Luz say, 'These bloody McCanns should just go away'."

The couple's spokesman, Clarence Mitchell, said: "We are not going to get into an argument with Robert Murat's lawyer.

"I would remind him that the McCanns have committed no offence in either Portuguese or British law.

"Metodo 3 retain our full confidence and are working diligently within the law."

A police source said no witnesses had complained of feeling pressured by the private detectives.