The families of 261 babies who disappeared in Spanish hospitals over five decades call for an investigation

Hundreds of Spanish babies were stolen from their parents by a secret network of doctors and nurses and sold for adoption, according to a petition filed in Madrid.

The families of 261 babies who disappeared in Spanish hospitals over five decades called on the attorney general to open an investigation into the scandal, after presenting evidence from former employees at maternity clinics and parents who admitted illegally adopting babies.

What started as a system for taking children away from families deemed to be politically dangerous to the regime of General Francisco Franco became an illicit business that continued at least until the 1980s, a campaign group has claimed.

Doctors, nurses, nuns and priests are all suspected of lying to mothers who were told their children had died during, or straight after, birth. Journalists investigating a clinic in Madrid at the centre of the allegations found a baby's corpse in a fridge, leading to suggestions that bodies were kept to show parents to prove their own child had died. Campaigners believe thousands of cases of stolen babies will eventually come to light.

"The father of a friend of mine admitted to him that both he and I had been bought from a priest and a nun from Zaragoza after being born in the Miguel Servet hospital," said Antonio Barroso, who discovered four years ago that he was adopted. DNA tests have proved that the people who raised him were not his real parents.

"There are cases that are accompanied by proof in the form of DNA tests and others that are simply mothers who suspect that their babies were stolen," said lawyer Enrique Vila, who represents the National Association of Irregular Adoptions. "We think it was an organised mafia."

Inés Pérez, 89, has confirmed that a priest encouraged her to fake a pregnancy so she could be given a child due to be born at Madrid's San Ramón clinic in 1969. Her adopted daughter, also called Inés, was among those demanding an investigation.

In a separate case, workers from an undertaker's in Malaga said they sometimes buried empty children's coffins that arrived from a local clinic.

The street outside the attorney general's office was blocked by weeping people today hoping to discover what had become of their lost children.

Many said they had been told that apparently healthy babies had died within hours of birth. They had never seen the bodies and the hospitals had taken care of the burials.