While that will probably not result in a significant increase in cost for light vans, the more complex systems needed to treat exhaust gases for heavier models is likely to add to vehicle cost because most will need a second treatment system.

This will be the system already used by trucks – selective catalytic reduction (SCR) – a system also used by Volkswagen on the outgoing Crafter. SCR needs Adblue, a liquid urea-based additive to work, meaning drivers need to top up another tank as well as the diesel from time to time. If drivers fail to do so, the on-board diagnostics system should reduce engine power until the Adblue tank has been re-filled. While truck drivers have become used to the system – and an infrastructure exists for distributing the liquid to truck users – making it available through all fuel forecourts is a different matter.

A recent visit to exhaust system manufacturer Tenneco suggests that by the time the Euro 6 limits come into force, the problem may have been solved. While SCR will still be needed for heavier vans, it seems likely that companies like Tenneco will have developed a solid urea additive system that will only need attention at regular services and will reduce vehicle cost.

The solid additive would be housed in the exhaust system and tests show that it could be more effective than liquid additive systems. The big advantage for operators is that drivers won't need to know which vans need additives and which do not.