Les Hammond, the firm's director of Risk Management Services, said: 'All too often the car becomes the mobile office and there are so many demands on the individual's attention that driving safely and with consideration to other motorists is virtually impossible.
'As we do not recommend drivers undertake any action that distracts the motorist from driving, we strongly advise against the use of mobile phones in the car. Traffic situations constantly change and an accident can easily happen in seconds.
'Although hands-free kits may be fitted in cars, these are not a solution to the problem as drivers have been proved to be equally distracted as when using a phone manually. Staff should not be expected to answer their mobile phones while driving and should schedule time to respond once they have completed their journey or are parked.'
He said drivers should switch off the phone before starting the engine and check for messages only when they had parked.
The company's 10-tips for safe phone use: