Which small, petrol cars will be exempt from the upcoming, extended ULEZ charges

Which small petrol car will be exempt from the new, extended ULEZ charges coming in October 2021? Looking for a used car and up to £4000.

Do older diesels do better with low mileage use?

I know that modern diesels don't take kindly to low mileage usage but wondered whether earlier diesels weren't so intolerant (pre-Euro4). Most of the cars in my price range are diesels due to the Government's...

If I get my old van converted to Euro6, will it become exempt from the ULEZ charge?

I have a Citroen Relay. It's Euro4, so it falls foul of the ULEZ in London. If I get it converted to Euro6, will Transport for London revise their assessment of the vehicle and exempt it from the ULEZ...