You lot have that advantage over there as we have fewer diesels than we should. I especially like the Rover TDis and we are (the NAS market) finally getting one next year!!
Did you ever see such a messed up situation in your whole life, son?
Nope. When your engine is hot it's fine (viscosity is a function of temperature) and a two tank system uses pure diesel to get up to temperature. Otherwise mix it in the tank with diesel and it's thin enough.
Of course I'd never do that in practice, as that would be tax evasion. Even if veg oil is half the price of diesel, I'd never consider it, Officer.