A construction company has been fined £100,000 and ordered to pay £33,000 in costs after a worker got an electric shock.

Philip Martyn was injured when the power was turned on while he was wiring a water unit at a building site in London.

While the 28-year-old, from Crawley, was working in one part of the site in High Holborn one of his colleagues had switched on the electricity from another area.

The Health and Safety Executive (HSE) took action against Mr Martyn's employers, CFR Group plc, because no systems had been in place for locking the power off.

It successfully pressed charges against the firm at the Central Criminal Court on Friday. (may 11) HSE Inspector Anne Gloor said: "The judgment goes to show that companies should ensure that all staff are safe at work, and that there should be good arrangements for locking off all power supply systems."

The HSE warned companies they must ensure the safety of all their employees or they would face similar action.

At the building site where Mr Martyn was received the shock there had only been tape on the power switches to indicate which circuits should be turned on or off.

The HSE said this indicated contractors on site were working excessive hours to get the job finished, which may have resulted in poor decision-making.

It said an investigation ruled CFR should have carried out a risk assessment for the work and ensured adequate signs were used to show which power circuit could be turned on. The HSE said other circuits should have been padlocked.

It said the Cheltenham-based firm should have had better procedures for a power lock-off and a better system for controlling access to the switch room.

The HSE said workers should not have worked longer than 48 hours within a specified reference period.

It criticised CFR for taking two months to provide it with addresses of the workers involved.

The firm had previously admitted breaching health and safety and working time regulations.

The HSE advised construction firms to consult it for advice on workplace safety. Further information is available at www.hse.gov.uk.