Sentencing of three companies involved in the Buncefield explosion has been set for 16 July, following their conviction for health and safety and environmental offences.

TAV Engineering Ltd and Motherwell Control Systems have both been found guilty of failing to protect their employees, while Hertfordshire Oil Storage Limited was found guilty of failing to prevent major accidents and limit their effects under the Health and Safety at Work Act. Motherwell Control Systems was not represented in court as it is in voluntary liquidation.

Hertfordshire Oil pleaded also pleaded guilty to causing pollution to enter controlled waters, which is contrary to the Water Resources Act.

The fire was said to be the largest in Europe during peacetime Photo: Royal Chiltern Air Support Unit

The Health & Safety Executive and the Environment Agency said: "This was the biggest and most complex criminal inquiry we have worked on together - the product of many hundreds of hours of painstaking forensic investigation.

"When companies put workers and members of the public at risk and cause environmental damage we will prosecute.

"When the largest fire in peacetime Europe tore through the Buncefield site on that Sunday morning in December 2005, these companies had failed to protect workers, members of the public and the environment.

"The scale of the explosion and fire at Buncefield was immense and it was miraculous that nobody died. Unless the high hazard industries truly learn the lessons, then we may not be that fortunate in future."

The explosion and subsequent fire injured 45 people and devastated homes and businesses in Hemel Hempstead. It was thought to have been caused by a fuel air explosion.

Total UK and British Pipeline Agency Ltd had already pleaded guilty to offences under the Health and Safety at Work Act and the Water Resources Act.