At present there is no legal obligation to publish such data – although it exists for all vehicles on the roads today.
Some makers give them out – but most don’t.
CAP values services manager Mark Norman said: ‘As political and regulatory pressure grows on businesses to understand and reduce their impact on the environment, the majority of fleet operators – who typically register 1.7 million new vehicles each year – are taking significant steps to reduce their carbon footprint.
‘But the lack of independent information on van fuel consumption and carbon dioxide emissions means they are unable to make fully-informed decisions on the environmental credentials of the 400,000 vans they commonly register each year.’
CAP is calling for vans to be included in standardised pan-European testing for mpg and CO2 output.
Mr Norman added: ‘Senior figures across the industry, from fleet managers to finance directors, are all under increasing pressure to achieve carbon neutrality.
‘In turn, some fleets are demanding their suppliers demonstrate green credentials and there is now a genuine commitment within the fleet industry to manage and mitigate its environmental impact.
‘And yet we are still unable to meet their need for independently derived fuel consumption and CO2 emissions figures for vans because that information is not made available to the UK market.’
The principal argument against independently tested standardised fuel consumption figures for vans is that they would not give a true picture because commercial vehicles are operated with widely varying payloads, he said.
Mr Norman added: ‘However, there is no reason why vans cannot be tested on a level playing field by running them unladen and fully loaded, to produce best and worst case scenarios. This would enable the end user to make comparisons between vehicles on the basis of their environmental impact.’