[QasimK]

That’s not right because it implies that only new cars since 2015 can drive inside the ULEZ.

The ULEZ standard requires diesel cars to conform to Euro 6, available since 2015 - the diesel emissions scandal notwithstanding. (The in-practice standards for diesel cars are much much more lenient than for petrol cars.)

The ULEZ standard requires petrol cars to conform to only Euro 4, required since 2005 but some cars manufactured as early as 2001 meet the standard including my 2002 MINI.

This means relatively few people are actually affected by ULEZ, compared to the implication that you need a car manufactured from 2015 onwards.