Forensic tests on the brother and sister of Madeleine McCann have shown that neither was sedated, it was claimed yesterday.

Portuguese newspapers have repeatedly alleged that hair samples from Kate and Gerry McCann’s children show that the couple sedated the two-year-old twins, Sean and Amelie, and Madeleine on the night that she disappeared.

But it is understood that the couple have commissioned their own tests, which found no traces of sedatives in hair samples from Sean and Amelie.

A source close to the couple said: “Any legal team worth their salt would have these kinds of tests done. No evidence of sedatives were found in the twins’ systems.”

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Madeleine disappeared from an apartment in Praia da Luz, southern Portugal, more than five months ago. Experts said that traces of any drugs would be retained in their hair.

Rachel Woods, the general manager of TrichoTech, a private toxicology laboratory that carries out tests on behalf of the Home Office, said: “Anything that enters the blood-stream also enters the root of hairs and stays in the same position as the hair grows. If there was nothing found in the hair, that’s pretty clear-cut.” David Gerrie, an analyst at Guy’s Hospital Medical Toxicology Unit, said: “Traces will remain in the hair until it falls out or is cut. Hair grows at about 1cm per month so to test for five months ago you would need a 5cm-long hair.”

Kate and Gerry McCann, both doctors, have vehemently denied sedating their children and have threatened to sue Portuguese newspapers that carry such allegations.

Clarence Mitchell, a spokesman for the couple, said: “I’m more than happy yet again to confirm that Kate and Gerry have never used sedatives on their children. Any suggestion that they did so is both hurtful and defamatory.”

The development came as Gordon Brown held talks about the Madeleine investigation with his Portuguese counterpart at the EU summit in Lisbon.

The Prime Minister’s official spokesman said that Mr Brown had a “brief discussion” about the case with the Portuguese Prime Minister José Sócrates.

The spokesman said: “They both agreed [that] what matters was there should be the closest possible cooperation between the Portuguese and British police.”

Mr Brown and David Miliband, the Foreign Secretary, have had telephone contact with Madeleine’s parents in the past, but lines of communication were cut when the couple were named as official suspects in their daughter’s disappearance.

The family yesterday released pictures of a plate that Madeleine made at nursery school for Brian and Susan Healy, her grandparents.

The plate was given to the Healys, the mother and father of Kate McCann, the week before the family went to Portugal. Madeleine’s palm prints are in pink and purple glaze and it carries comments written by a teacher, saying: “I love you Grandma and Grandad. From Madeleine. 2007.”

Mrs Healy said: “Madeleine made the plate at her nursery school in Queniborough. The teacher helped with the writing. Madeleine’s contribution was her handprints.

“Madeleine told me that she had made this present for me. Kate said, ‘Tell Grandma what you’ve got for her.’ A week or so afterwards they went to Portugal and while they were [there] my brother Brian and his wife Janet came to stay with us in Liverpool and they gave me the plate.

“And it was literally days afterwards that Madeleine went missing. It was my last gift from Madeleine. It is very, very precious because of that fact.”

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