A woman who wrongly suspected her husband was having an affair with a colleague allegedly drowned their three-year-old daughter in the bath, a jury has been told.

Former science teacher Claire Colebourn wept as jurors were told she mistakenly believed her CEO husband Michael was cheating on her with a fellow executive at the firm where they worked.

Colebourn, 36, allegedly murdered their daughter Bethan at their home in Fordingbridge, Hampshire, before trying to kill herself.

Bethan’s body was found the next day in a downstairs bed, her hair still wet, Winchester crown court was told.

In the days before the alleged murder, Colebourn researched drowning on the internet and also looked for information on churches and cemeteries, it was claimed.

After her arrest, Colebourn told police she had held Bethan under the water, the court heard. She wrote a letter to her parents while in custody in which she claimed: “In my eyes I saved her.”

It is claimed she also informed police Bethan had told her: “I don’t want a bath, Mummy, I don’t want a bath.”

Opening the prosecution case, Kerry Maylin said Bethan was found dead at the family home in October 2017.

Maylin said: “Bethan was put in the bath and held under the water by her mother. When she was found, she still had wet hair.”

The prosecutor said Colebourn and her husband had been together for 16 years and married in 2011, but their relationship had deteriorated after their daughter was born.

Maylin said: “Claire had unfounded thoughts in relation to her husband having an affair with a colleague.

“She contacted her husband’s work by email. She said: ‘Michael Colebourn walked out on his family, his wife, his daughter, his dog and horse.’”

Maylin told jurors Michael Colebourn last saw his daughter alive a few days before when they visited a park. Colebourn fought back tears as he told the court that she had been happy and kissed him goodbye.



He told the court: “Claire was not happy I was seeing Bethan but eventually she allowed me to have her for the day. I dropped Bethan home about 5pm. Bethan kissed and hugged me, then went into the house. She was happy, she was pleased to see the dog. She was fine.”

Claire Colebourn posted two letters, one to a police station in Bournemouth, Dorset, detailing what had happened to her relationship with her husband and the second to her mother telling her she loved her. In both letters, jurors heard Colebourn asked to be cremated and buried with her daughter.

Maylin added: “It is very likely that, by the time Claire posted the letters in the early hours of 19 October, Bethan had already been killed by drowning in the bathtub.

“Claire’s mother found her granddaughter. Thinking she was asleep, she went to find her daughter. She describes her being in a diabetic hypo.”

Claire Colebourn denies one count of murder. The trial continues.