I'd like to see someone do analysis on what percentage of "Zero emissions capable" London taxis actually spend any reasonable proportion of time powered by electricity.

I suspect the drivers, not wanting to wear out their batteries, set the vehicles to use the engine the whole time, which is a built in feature (the 'save' drive mode)...

It's time we said "no taxi may run an engine inside zone 1, and if they do it's an £80 fine".