VOLVO'S new diesel engine is set to cost business motorists more than they bargained for under the new company car tax rules.

Carbon dioxide emission figures for S60, V70 and S80 models powered by Volvo's D5 common rail motor have had to be revised upwards after a second series of tests.

The adjustment could leave drivers liable to pay several hundreds of pounds more in benefit-in-kind tax over the next three years.

When it launched its first turbodiesel unit to the press in July, Volvo claimed a CO2 figure of 161g/km for its D5 S80 model. But last week, Ian Townley, managing director of Stoke-on-Trent ceramic print company Capper Rataud, found a different figure - 172g/km - on the V5 paperwork for the £25,040 car he has ordered for delivery in December.

The difference in emissions will see Townley's Volvo S80 D5 taxed at 19 per cent (including the 3 per cent diesel penalty) of its P11D value from next April, instead of his budgeted 18 per cent, and then in the 2003-04 tax year the discrepancy will open to two percentage points. 'As a 40 per cent taxpayer, the change will cost me a further £100 in tax for the first year and an extra £200 in both years two and three. I'm still having the car, but this leaves a sour taste,' said Townley. 'I couldn't believe it because I was particularly impressed by the figures of 158g/km for the S60, 169 for the V70 and 161 for the S80 that I'd seen in Fleet News. The same figures appeared again in material that Volvo supplied to its sales force, and it was a big part of the reason why I chose the S80,' he said.

A Volvo spokesman said: 'During initial testing, the lower figures were achieved, and so these were publicised. Once the production line was up and running, the authorities carried out further testing and found the figures were higher, so these are the ones that now have to be advertised.'