HUNDREDS of thousands of companies have not supplied the Inland Revenue with up-to-date details of company cars, risking chaos next April when company car tax rules change.

According to the Inland Revenue, only 10 per cent of firms have responded to the mailshot sent to every company car fleet in the country in June asking for CO2 emission figures and fuel type for vehicles registered before April 6, 2001.

Inland Revenue policy advisor Mary Braim said thousands of drivers will be paying the wrong amount of tax next spring, and warned that fleet managers, who may not be at fault, will bear the brunt of their anger. She said: 'We have had a better response from small fleets, but many have done nothing. If we do not receive them back, company car drivers' tax will be based on last year's information.'

Braim said a reminder had gone out in September but the Inland Revenue had yet to see any concerted response from companies.

'We are trying several ways to get to people,' she said. 'We will be sending out details to the drivers in January, and firms can get hold of the mailshot through our website.'