Car appreciation... the aesthetics, the engineering, etc

You can apply with the DVLA stop paying vehicle tax if your vehicle was built more than 40 years ago. This date moves forward on a 40-year rolling system. For example, when the ULEZ launched in April 2019, vehicles built before 1979 were eligible to apply for historic vehicle tax class.

All vehicles that have a historic vehicle tax class are exempt from the ULEZ.

From: https://tfl.gov.uk/modes/driving/ultra-low-emission-zone/discounts-and-exemptions#on-this-page-5