A devoted Cotswolds mum accidentally drowned her disabled daughter in the bath and then carried her into a nearby lake where she drowned herself, an inquest heard.

Celebrity florist Judith Richmond believed she was giving her nine-year-old child Amelia, who suffered from cerebral palsy, an experimental treatment at their luxury lodge at The Landings, South Cerney, near Cirencester.

She was obsessed with the idea her daughter, known as Millie, had been misdiagnosed and was suffering from metal poisoning instead – and that the land itself was also poisoned by metal.

Gloucestershire Coroner Alan Crickmore said he believed the distraught mother had been mentally unbalanced.

"I am satisfied in the days leading up to her death and Millie's death that Mrs Richmond was suffering from a manic depressive episode and as a result, her behaviour was bizarre and uncontrolled," he said.

Jude and Millie disappeared on March 15.

Their cleaner discovered the deserted house with the front door ajar and scattered with flannels, towels, food containers, a half-full bath with a flannel flecked with blood. Cars, car keys and mobile phones were all still there.

Their naked bodies were found three days later by police divers, following a huge appeal for news of their whereabouts.

Recording his verdict at Cirencester's Registrars yesterday, where Millie's step-father Nick Richmond had been shaking his head in despair, Mr Crickmore recorded an accidental death verdict on Millie and an open verdict on her mother because of her mental state.

Expert pyschiatrist Dr Laurence Mynors-Wallis said in his written evidence: "There's no evidence Mrs Richmond was planning to take her own life or that of her own daughter.

"Mrs Richmond's symptoms were typical of a manic phase of a bi-polar disorder."

He said there was a history of bi-polar disorder in Mrs Richmond's family and significant stresses could have triggered her actions.

These included the 'on-going stress' of Millie's condition, the rocky relationship with her husband Nick and the 'disorientation' of having just travelled through different time zones coming home from New Zealand which she had visited with her husband with plans of emigration.

Mrs Richmond was a world-renowned florist whose customers had included the Queen Mother and rock legends Pink Floyd. She created bouquets for film blockbuster Bridget Jones's Diary and worked for several famous opera productions as well as Hollywood film premieres. But in the final months the hearing heard her behaviour had become more and more erratic.

She had become 'obsessed with finding old flames', told family, friends, neighbours and even complete strangers she was seeking a cure for Millie's metal poisoning and hoped to receive help from celebrities Simon Cowell, Max Clifford and David Coulthard for Millie's treatment. She believed all human beings were aliens on the planet and were all being killed by metal.

She urged neighbours to use Swatch watches as they didn't contain metal or eat anything which came out of the ground as it was contaminated.

Mr Crickmore said just before the pair's disappearance she borrowed butter from a neighbour saying she was going to 'draw the toxins' out of Millie's body.

The coroner said: "The most obvious assumption is that in trying to assist Millie with one of the experimental treatments by massaging her with oils in the bath, somehow Millie drowned and was carried to the lake by her mother who perhaps realised the enormity of the accident which had just occurred and took her own life.

"The second possibility is that they went to the lake together, probably at Mrs Richmond's insistence to get away from the house and the metal and all of those things which she thought to be harmful to Millie.

"Either of those two scenarios is entirely speculative but on the balance of probabilities I think it is more likely than not that Millie died in the bath."

After the verdict Mr Richmond hugged family and friends and said: "It was tough."