Kate McCann pictured yesterday as she was leaving The Catholic Church of The Sacred Heart near to the family home in Rothley, Leicestershire

Kate and Gerry McCann are considering legal action today against 'hurtful' claims that they gave Madeleine and their twins sedatives on the night the four-year-old disappeared.

The McCanns were responding to speculation in the Portuguese press that the couple, both doctors, administered the drugs to all their children.

Their lawyers were today considering legal action against newspapers which publish the claims.

The McCanns' spokesman Clarence Mitchell said: "Contrary to renewed speculation in the Portuguese press, Gerry and Kate McCann wish to make it categorically clear that they have never, ever used sedatives on their children.

"To suggest otherwise is as outrageous as it is hurtful. Lawyers for the McCanns will be monitoring British coverage of the latest Portuguese claims very closely and will take action if it's felt necessary."

Portuguese newspaper '24 Horas' says that forensic evidence analysed by both Portuguese and British experts proves that all three children had been drugged.

The report suggested that Madeleine's brother and sister Sean and Amelie may also have been sedated because it had earlier worked with Madeleine herself.

The news comes after yesterday's claims that police are now investigating 'significant' evidence that Madeleine was left in her parents' apartment with six other children, including Sean and Amelie, on the night she disappeared.

Detectives believe the seven friends holidaying with Kate and Gerry McCann in Portugal also left four of their young children in the couple's apartment.

Yesterday, police said that the presence of so many youngsters would make it highly unlikely that four-year-old Madeleine was abducted.

Up until now, it was thought Madeleine was left with just her brother and sister, two-year-old twins Sean and Amelie, while the adults in the party went out to eat in a nearby tapas bar.

Holidaymakers at the Ocean Club complex in Praia da Luz said three plain-clothes officers revisited the McCanns' holiday apartment at 7am yesterday and stayed inside for up to five hours.

The apparent activity at the flat comes days before the floundering investigation is to be taken over by another officer, Paulo Rebelo, who is said to favour a review of every aspect of the search so far.

The McCanns' spokesman Clarence Mitchell denounced the latest claims as part of a smear operation.

Police are investigating 'significant' evidence that Madeleine McCann was left in her parents' apartment with six other children on the night she disappeared

Portuguese detectives have regularly briefed Portuguese journalists that they think the socalled Tapas Nine have lied about the events of that fateful night.

"It's utter rubbish," said Mr Mitchell.

"If you put seven children together, you're going to have a far harder time getting them to sleep than three."

Police sources told Portuguese newspaper 24 Horas they had 'significant evidence' that seven of the group's eight children - all under the age of five - had been in the McCanns' apartment on May 3. They gave no explanation as to the whereabouts of the eighth child.

A source close to the family said the group had regularly visited each other's flats during the six-day holiday before Madeleine vanished, but insisted the children all slept in their own apartments.

As a new police detective takes over the case, police have appealed for the DNA of all British holidaymakers staying in Praia da Luz after evidence suggested Madeleine could have been abducted.

According to Portuguese sources, a number of samples recovered from the Mark Warner have not been identified - and are potentially from the kidnapper.

British officers have now been instructed to collect the DNA and fingerprints of every UK tourist who was on holiday there at the time to eliminate them from the inquiry.

Portuguese police are once again re-focusing their investigation on the apartment where they now believe seven children, including Madeleine, were sleeping.

Seven officers spent around five hours inside the building today as they continued to persue a case against Kate and Gerry McCann, who have been named as official suspects in their four-year-old daughter's disappearance.

There are convinced that the apartment "holds the key" to solving the case.