Shannon Matthews was systematically doped with anti-depressants and a cocktail of prescription drugs including opiates, it can be revealed today after her mother was convicted of the child’s abduction.

Karen Matthews and Michael Donovan, her boyfriend’s uncle, were found guilty of kidnap, perverting the course of justice and false imprisonment in a unanimous verdict by a jury at Leeds Crown Court this afternoon.

During the seven-week trial the jury was told that Shannon was drugged with sleeping pills for at least 20 months before her imprisonment.

The court was not told that toxicology tests showed that Shannon had also been given a further three prescription drugs - two potent painkillers and an anti-depressant - over the same period.

All three, amitriptyline, tramadol and dihydrocodeine (DHC), which have the side-effect of causing sleepiness, were prescribed for Donovan.

Their combined impact would be likely to have created a child who was docile, passive and compliant.

The doping of the young schoolgirl may even have happened over more than 20 months. That was merely the growth period of the 20cm-length of shoulder-length, medium-brown hair taken from Shannon for testing.

During the trial the court heard that the nine-year-old had also regularly ingested two lots of sleeping pills.

These were temazepam, a "potent hypnotic" drug which has powerful sleep-inducing effects, and a travel sickness medication, Traveleeze, whose active agent, Meclozine, has the side-effect of causing drowsiness.

It was not possible to establish whether the same drugs had been fed to the other children living with Karen Matthews, because she refused to give permission for the necessary tests to be carried out.

All of the drugs found in Shannon, with the exception of Traveleeze, which can be purchased over the counter, had been prescribed to Donovan, the man convicted today of the child's kidnapping and false imprisonment.

Craig Chatterton, a forensic toxicologist with the Forensic Science Service, told The Times that he was initially asked to test a urine sample taken from Shannon less than a day after she was rescued in March.

He was asked specifically to look for Traveleeze, because boxes of the product had been found in Donovan's flat at Batley Carr, where police found the schoolgirl hidden in the base of a divan bed.

The urine tests, which only cover a period of up to three days before the sample was taken showed, that Shannon had been given both the travel sickness pills and temazepam.

Dr Chatterton next asked to analyse a pencil-thick sample of hair, which would reveal traces of any drugs ingested over a longer period.

Tests were also carried out, over a period of time, to establish how quickly Shannon's hair grew. In her case, as with most people, the rate was about 1cm per month.

The discovery that five different drugs, inlcuding one opiate, were present in each 1cm length of the 20cm tested, showed that the girl had been subjected to a consistent pattern of doping over a prolonged period.

That four of the five were prescribed to Donovan was a strong indication of a much closer relationship between the kidnapper and the child's immediate family than either defendant was prepared to admit.

Both denied any role in giving drugs to Shannon, although Donovan said that he had purchased and given her Traveleeze because he wanted to take her on car outings to local parks and supermarkets. Police are convinced that the girl was never allowed to leave the flat.

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