Civil engineering firm Kier has been fined more than £4m after its workers struck overhead powerlines twice while working on the M6 motorway, causing cables to land in the path of passing vehicles.

In one incident, an overhead cable the workers brought down hit a lorry. In an earlier incident, a cable landed on the motorway.

An investigation by the HSE found that Kier workers failed to immediately tell network provider Scottish Power about one of the incidents.

Both incidents happened on overnight road works, part of the smart motorway scheme between junctions 16 and 18 near Sandbach in Cheshire.

During the first incident, a team of three workers were working a nightshift on 28 March 2018. The workers were clearing tarmac from the hard shoulder and loading a truck with a digger. As the driver moved the truck along with an attached loading bucket raised it struck and severed a 11kV overhead powerline that landed in the motorway and in a nearby field. The company failed to immediately tell Scottish Power, which meant the cable was reenergised a number of times while it was lying on the motorway and vehicles were passing.

During the second incident, another team of three workers from a sub-contractor were removing a temporary motorway barrier on 21 January 2019. The crane arm attached to their lorry loader struck an overhead cable, which led to an unmarked 11kV powerline being hit and snapped by an oncoming lorry.

The HSE found that inadequate planning from Kier meant the vehicle used in the first incident was unsuitable, despite other more suitable vehicles being available. There was also no task-specific risk assessment available for the workers.

In the second incident, the workers said that they were unaware of the overhead hazards.

In relation to the first incident, Kier Infrastructure and Overseas Limited pleaded guilty to breaching Sections 2(1) and 3(1) of the Health and Safety at Work etc. Act 1974. In relation to the second incident, they pleaded guilty to breaching Section 3(1) of the Health and Safety at Work etc. Act 1974 and Regulation 13(1) of the Construction (Design and Management) Regulations 2015.

In total, the company was fined £4.415m and ordered to pay costs of £87,759.60 at Manchester Crown Court on 12 January 2023.

HSE inspector Mike Lisle said:

“This is a significant fine reflecting the seriousness of the failures here. The company’s failure to plan the work properly and provide an adequate risk assessment put its workers and those using the motorway in significant danger.”