One of Britain's foremost forensic experts has been called in to lead a new series of laboratory tests that could pinpoint the killer of housewife Ann Heron.

Mrs Heron's body was found at her Aeolian House home, on the edge of Darlington, in August 1990. Her throat had been slashed.

The murder investigation has become one of the longest running in Britain, with detectives always remaining hopeful that advances in DNA technology would lead to a breakthrough.

Today, Durham Police announced that a leading forensic expert from the North-West had been brought in to oversee the scientific investigations.

The force said that technological advances in recent months would allow experts to conduct detailed examinations of tiny samples from the murder scene, so small that, until now, they had been beyond analysis.