If he doesn't stop King Khan from expanding ULEZ in London, Labour will lose heavily many usual labour voters. There are thousands of diesel car owners in Greater London who will pay £12.50 EVERY day that they drive to work, the dentists, the GP, hospital, down the pub, doing a Tesco run etc etc etc. People won't wear it. Starmer must either back it and lose or force Khan to back off, even for five years, and then pick up the votes.
I live on the south coast and to visit close relatives in the southern area of London, just, will cost me I reckon £600 a year.