Mark Norman, head of residual value forecasting at CAP, believes the huge rise in the number of diesels in the past year shows that Government tax changes have a profound effect on buying trends, and as a result the Government could have done more to stimulate demand for fuels such as LPG.
He said: 'If the Government was really serious about promoting cleaner fuel it should have used the new benefit-in-kind taxation system to give LPG drivers a real incentive.
'The surge in diesel uptake has proved that taxation really impacts on vehicle choice. If you reward those who choose clean fuel manufacturers are only too willing to meet demand.
'With such a boost, after two or three years LPG cars would be a common sight even on the used market and people would feel far more comfortable choosing one.'
Andrew Ford, corporate affairs manager at Calor Gas, was more positive about the Government's intentions to promote LPG, citing the freezing of duty on the fuel for the next three years as an indication of its commitment.
He said: 'When you change tax policy so radically as the Government has done, you are not going to get it right first time. We are optimistic the anomaly is being worked on and will be resolved in the next few months.'
For the new tax system, drivers of dual-fuel LPG cars are charged differently according to whether the car was manufactured to run on LPG or whether it had an aftermarket conversion.