This view was put forward by Eric Johnson, a Swiss-based environmental scientist, in research for LPG supplier Calor Autogas. Calor used the show to help spread the LPG message among fleets and showed how the greener fuel was a better option than petrol and diesel on several fronts.
For example, said Johnson, the source of LPG is in the North Sea and there is enough to supply Britain if supplies from the Middle East dried up.
Johnson also argued the case for LPG in terms of global warming, emitting 10 times less particulate matter than the cleanest diesel engines using particulate traps. He also pointed out that many other boroughs than London were looking at setting up congestion-charging schemes so fleets would be advised to look at alternative fuels as a way of avoiding extra charges.
He said: 'It is likely that congestion charging will spread across the UK. It is undeniable that traffic pollution has a major effect on public health. If local authorities are claiming their schemes will improve public health as well as ease road transport, then they must recognise the beneficial impact of alternative fuels.'