Diesel (At least for private cars. There's no realistic alternative commercially unless they radically change the tax regime and sort-of-forget-about greenhouse gasses) is now on a government hit list, with special scrappage schemes and punitive fuel taxes proposed.
The fuel tax might bring used car prices down, but a proposed scrappage scheme is likely to put them up as people buy speculatively with a view to cashing in.
I had a Perkins diesel Maestro I liked a lot, but they'll be VERY rare now, not really "luxurious" (Montego maybe a bit more) and I dunno what long term reliability is like. Only other diesel I've had was an ex-BT Renault Dodge workshop truck.