A national energy supplier has been ordered to pay more than £500,000 in fines and costs after it fell “significantly short” of the standards of reasonable practicability in failing to safeguard a worker who was electrocuted, a judge has concluded.

Norwich Crown Court heard that the incident took place at UK Power Networks’ (formerly known as EDF Energy Networks Limited) facility in Diss, Norfolk on 9 November 2007. The company supplies power to London, as well as to the eastern and south-eastern regions of England.

Jonathan Crosby, 45, worked as an overhead electrical linesman at the site, and was asked to remove an electrical transformer from the top of a pole connected to overhead power lines. He was lifted up inside the basket of a cherrypicker and proceeded to detach the transformer but, as he did so, he came into contact with live power lines and suffered a fatal electric shock.

An investigation by the HSE found that UK Power Networks failed to cut the electricity supply by removing the fuses from the transformers. HSE inspector Toni Drury revealed that there was no safe system of work at the site, staff had not received proper training to carry out the work safely, and there was inadequate supervision of the operation.

Inspector Drury said: “A family man has lost his life in tragic circumstances, which could have been avoided if essential safety measures had been put in place by UK Power Networks. This tragedy illustrates how dangerous work on or near overhead power lines is, and it is imperative that employers ensure there are safe systems of work, and that these are implemented and followed.

“There is no room for error when working with such high voltages. It is not only the person involved in such an awful incident that is affected but family and friends are often left behind to deal with the devastation.”

UK Power Networks appeared in court on 31 August and pleaded guilty to breaching s2(1) of the HSWA 1974. It was fined £300,000 and ordered to pay £219,352 in costs.

When delivering his sentence, Judge Peter Jacobs said: “They fell significantly short of the reasonable-practicability standards and they must take responsibility for their organisational and operational failures. It is obvious that the work being done is very dangerous and the merest contact could result in electrocution, or a fall from height.”

After the hearing, a UK Power Networks spokesperson told SHP: “UK Power Networks has owned the electricity networks in the East of England, South East and London since October 2010. By our guilty plea back in June, we acknowledged our responsibilities for what happened on the day. We remain committed to ensuring the highest standards of health and safety in everything we do.

“Following the incident immediate steps were taken to suspend working on live electrical equipment until the investigation had been completed and all staff involved in similar work had been retrained. The extensive programme of improvements that was in place was continued and reinforced.”