LANCASHIRE County Council has launched an inquiry into the killing of one of the its social workers.

Father-of-three Philip Elison was stabbed to death while conducting a home visit as part of his job with the council on Monday.

The council, which has social services staff working across the county, has promised a "very thorough" investigation into the circumstances surrounding the death of 47-year-old.

He died after alegedly being attacked when he went to a house in Fulwood, Preston.

Union bosses have given their backing to the move.

Councillor Chris Cheetham, Lancashire County Council's cabinet member for adult and community services, said the council would work with Lancashire Care NHS trust to see whether the correct risk assessments were carried out.

He said: "This is a tragic incident and we are determined to learn whatever we can from it, so it will be a very thorough review.

"It is a delicate balancing act because obviously the police are investigating, but we have already started speaking to his colleagues, and we are looking at the background to what happened."

Neil Linsky, a regional officer for Unison, added: "We would expect the employer to do all necessary risk calculations.

"We don't know in this case what, if anything, has gone wrong.

"They do need to do an investigation and it's going to have to be open and transparent.

"If the social worker has gone on his own I would suspect it was not expected to be dangerous - where there is danger you sometimes get two workers going."

The killing took place in a two-storey house on a cul-de-sac, part of a small estate of newly-built housing association properties.

A post-mortem examination on the Lancashire County Council worker's body will take place on Wednesday morning.

A 51-year-old man was arrested at the scene and has been detained under the Mental Health Act.