THE number of fleets implementing diesel-only policies has doubled in three years, new research suggests.

A study by fleet and fuel management company Arval found that 31% of fleets are enforcing diesel-only policies, up from 25% last year and 16% in 2003.

It also found that new variations of such policies, including ‘diesel for all except senior staff’, are in place in another 17% of fleets, up from 13% last year. The study questioned 430 fleet managers and fleet policy decision-makers responsible for more than 100,000 cars.

Mike Waters, head of market analysis at Arval, said: ‘It is clear from this research that the gradual evolution of the UK company car fleet towards diesel and away from ‘perk’ vehicles continues and is, in fact, outstripping many fleet managers’ expectations. We expect this rate of growth to continue, particularly if the UK Government incentivises the use of cleaner diesel vehicles in line with the forthcoming Euro V regulations.

‘The pressure is now clearly on manufacturers to achieve this next level of standard, as the ones that get there first will be at a considerable advantage and are likely to increase their penetration of fleet.’

Last week on Fleet NewsNet, leasing company LeasePlan suggested that diesel engines account for three-quarters of the UK’s company car parc.

The main reason is the change to company car tax in 2002, when tax became based on carbon dioxide emissions rather than business mileage.

The number of diesels on UK fleets has increased every year since 2001 – a trend which is also being reflected in retail.