THE cheapest cars to operate in the UK market are the Ford Ka 1.3i and Suzuki Alto 1.0 at 13.8p per mile, according to new figures from CAP Motor Research. Both models head the list of the 40 cheapest cars to operate as they have done for the past two months, according to the July survey.

Analysts stress that the headline figures of servicing and fuel economy - relied upon so much by manufacturers in promoting their cars - remain the least significant running cost factor. Depreciation accounts for between a half and two thirds of the total running costs calculated by CAP analysts, who base their figures on three years/60,000 miles. Depreciation is calculated from CAP Monitor using manufacturers' list prices, including delivery but excluding road fund licence, minus future residual value.

The cheapest diesel on the road, taking eighth place, in the top 40 is the Mazda 121 1.8 DXi three-door at 14.3p per mile, while the best performing automatic is the Nissan Micra 1.0 Shape three-door.