Police will not question the widow of a man who was helped to die at a clinic in Switzerland at this stage of their inquiries.

Motor neurone disease sufferer Reg Crew, died on Monday in Zurich.

Merseyside's chief constable Norman Bettison revealed in an open letter that his force did not yet intend to question Mr Crew's widow, Win.

Mr Bettison said the force had consulted extensively with the Crown Prosecution Service and still believed a full investigation was necessary, but without causing Mr Crew's family further distress.

Mr Crew, of Hunts Cross, Merseyside, was thought to be one of the first UK citizens to take advantage of more relaxed laws on assisted suicide in Switzerland.

Grief-stricken

Mr Bettison's letter said: "At this stage we hope to be able to carry out the enquiries without having to bother Mrs Crew's wife or close family.

"Whilst we need to fulfil our responsibility we are conscious that this is sad and awful time for Mrs Crew and her family and have no wish whatsoever to compound the grief they must be suffering at this time."

Assisted suicide remains illegal in the UK, despite a number of legal challenges.

The former docker, who was 74, had suffered from the debilitating disease for more than four years.

He died after taking a fatal dose of barbiturates prepared by a doctor.

Mr Crew faced creeping paralysis if he remained alive and killed himself with the help of the "assisted suicide group" Dignitas in Switzerland.

Swiss law does not state that assisted suicide is legal but the practice is widely considered as a "humane act".

Prosecution is extremely unlikely unless the person helping is proven to be acting out of self-seeking motives.

On Wednesday it was revealed that production staff on ITV1's Tonight - fronted by Trevor McDonald - could face police questions about the assisted suicide.

The team, who accompanied Reginald Crew to a clinic in Zurich where he died on Monday, were making a programme about the case that is due to be broadcast on Friday.