UK gas transportation company Transco has been given a record GBP15 million fine for breaking health and safety laws after a mains explosion caused the death of four family members.

The fine is by far the largest handed out in the UK to a single company found guilty of breaching health and safety laws. It is seven times that imposed on Thames Trains after the Ladbroke Grove train disaster, which killed 31 people.

Jurors concluded after a six month trial at the High Court in Edinburgh that Transco was responsible for a leaking mains line underneath the Lanarkshire house of the family of four that died in the explosion. Transco had believed that the mains equipment was made of safer newer material due to erroneous records and as a result vital maintenance had not been undertaken.

The 13-strong jury unanimously convicted Transco of breaching the 1974 Health and Safety at Work Act for allowing the iron gas main that ran through the family’s property to extensively corrode and leak. Judge Lord Carloway imposed the record penalty.