FLEET operating costs are set to rocket as more hi-tech gadgetry and safety features are incorporated into vehicles. Insurers say the fast approaching new breed of 21st century intelligent environmentally 'green' cars - some of which could be remotely controlled from the roadside - could be so complex that their repair costs will drive insurance premiums into an 'uncontrollable upwards spiral', it was claimed this week.

The warning came from Thatcham - The Motor Insurance Repair Research Centre - which, while welcoming the developments, said car makers and environmental and safety legislators must be fair to motorists. 'Advanced technology must not present fleets and private car owners with soaring repair bills,' warned Thatcham chief executive Michael Smith.

Acoat Bodyshop Services, which is owned by the 100 independent bodyshops which form the network, says structural modifications and other safety changes to cars inspired by crash tests under the European New Car Assessment Programme, will result in rising repair costs. Managing director David Wallace said: 'Generally cars which have more safety equipment are more difficult to repair and therefore more expensive.'

However, Thatcham says it can help manufacturers manage repair costs and ensure they don't break fleet budgets by checking that expensive sophisticated gadgets are located in 'out of the way' places. While many of the hi-tech gadgets and safety features are only incorporated in more expensive cars, by the turn of the century even the smallest cars would have a mind of their own to minimise exhaust emissions and provide high occupant safety, said Smith.