The emphasis in our media has been about extending these to all our other major cities, in time. Basically ... large cities will naturally attract businesses to them. Along comes some (usually Leftie) authority or other, to find a way of taxing the guts out of travel within them !
As for London, though .. there are indeed plans afoot to expand the coverage area ! Courtesy of our Left-supported, Trump-bashing Muslim mayor, then (this naturally comes with supportive text to help sell it, as, after all, the Guardian is a Leftie paper !) .. see ..
https://www.theguardian.com/environm...zone-pollution
This link carries an image of the intended area (which I've tried but failed to copy, to present it in this post .. check the link if interested). It doesn't QUITE cover
ALL of London, but it comes close !! Enfield, for example, marks the northernmost borough in London.