A dentist accused of murdering his wife and his ex-lover’s policeman husband is on suicide watch in prison.

Dr Colin Howell (50) was transferred from his remand cell to the jail’s hospital at Maghaberry because of severe stress and depression. Senior staff decided on the move after becoming worried about his mental state, and Howell (pictured right), from Castlerock, Co Londonderry, is now having treatment under close medical supervision.

The Prison Service last night refused to comment on his hospital admission, but authoritative sources confirmed the dentist, who is charged with the double murder 18 years ago, was on “suicide watch” because of stress and depression. It is understood the decision to transfer him out of the prison’s Bush House wing was taken just hours after he appeared via video link, looking tense, at North Antrim Magistrates Court in Coleraine on Monday.

Howell, a father of 10, has been in custody since his arrest in January when detectives launched a murder investigation into two deaths which were first thought to have been suicides.

The bodies of his wife Lesley (31) and RUC officer Trevor Buchanan (32), his then lover’s husband, were found in a car filled with carbon monoxide fumes at Castlerock in 1991.