Will ULEZ expand beyond the M25 or to other cities?

Currently, the ULEZ zone stops at Greater London's boundaries (within the M25). Transport for London has no announced plans to expand further. However, other UK cities, including Birmingham, Bristol, Portsmouth, and Bath, have introduced Clean Air Zones (CAZ) with similar emission-based charges. 

While Essex and Thurrock aren't planning similar schemes, buying a ULEZ compliant vehicle future-proofs your purchase against potential regulatory changes and maintains higher resale value.