A man who killed an Irish mother of three with a bolt gun has been jailed for at least 20 years at the Old Bailey in London.

John McFarlane pleaded guilty to what was described as the clinical murder of Mary Griffiths who was originally from Dublin.

38-year-old Mary Griffiths had contacted police in Suffolk, where she lived, to complain that McFarlane had been stalking her.

In May, John McFarlane broke into Mary Griffiths' house in Suffolk and dragged her from her bed before shooting her in the chest three times with a bolt gun from an abattoir.

A neighbour described the murder as 'clinical deliberate and like an execution.'

The separated mother's three daughters were in the house at the time.

McFarlane was taking revenge after Mary Griffiths had posted a message on Facebook saying he was delusional if he thought they would ever have a relationship.

John McFarlane later texted a friend saying he had taught her a lesson before slashing his own wrists in an apparent suicide attempt.

Family members from Ireland were in the Old Bailey court to hear the sentence.

The judge told McFarlane that Mary Griffiths' parents would have to endure the appalling experience of attending the funeral of their own daughter.

Britain's Independent Police Complaints Commission is investigating why police did not respond to Ms Griffiths' call complaining of harassment on the day before she was murdered.