His comments at the third annual City of Westminster Driving the Change conference add fuel to an already fierce argument, with alternative fuel vehicle manufacturers claiming their products provide long-term advantages over petrol or diesel. They are backed by several fuel suppliers, but some leading industry figures have claimed bi-fuel vehicles will not keep up with the improving level of emissions from petrol and diesel vehicles.
Watson backed their argument, saying: 'Vehicle emissions are falling. By 2006, European emissions standards will slash emissions on new petrol and diesel vehicles and that will reduce or virtually eliminate the advantage of gaseous-fuelled vehicles.' However, he was careful not to extend his claims to an attack on the alternative fuel industry, saying: 'I am not claiming that it will not have an advantage at all, but the difference in absolute terms between alternative fuels, petrol and diesel will be very small.'
His comments drew a swift reaction from Jonathan Murray, manager of the Powershift programme, who said: 'I think he is completely misunderstanding what can be done. Even with a small improvement in emissions, when that is multiplied over the whole alternative fuel car park, the benefits in emissions nationwide are massive.' Furthermore, he argued, most conversions are based on petrol engine technology, which meant they would simply provide an even cleaner conversion of a cleaner engine.