Hello. I'm new to the forum.
Anyway, I recently emailed my local MP to ask why Euro 6 vans incur higher road tax than Euro 4 or Euro 5, asking her to take it up with the Chancellor.
She replied, saying she could see no reason for this other than the road tax system for vans is outdated; she said she'd ask the Chancellor and would get back to me when she's received a reply.
If, like me, you have a Euro 6 van (even if you don't have one!), please write to your MP, asking them to pursue this. Maybe, just maybe, if enough people do this, it might make a difference.
(Tip: you'll have to include your name and address so that your MP will be able to respond under parliamentary rules.)