The man, who works for Siemens Transmission and Distribution (Energy Sector) as a site installation engineer, was checking electrical equipment on site.

It has not been revealed on how he got the shock but PrintWeek understands he was badly burned.

Following the accident he was transferred to the Burns Unit at Broomfield Hospital in Chelmsford where he remains.

A statement from Siemens said: "Our thoughts are with him and his family and with his colleagues, who are shocked and upset by what has happened. It is too early to give more details about this incident. We are in touch with our employee's family.

"The Health and Safety Executive are involved and we will co-operate fully in an investigation of the causes and circumstances of this incident as well as carrying out our own investigation. Siemens has a strong culture of health and safety at work which is a priority for us."

A statement from News International said: "Our thoughts are with the worker and his family."

The company also said that production started late Thursday evening because of the incident, but a full print-run was completed overnight. Full operations have now resumed.