[pwagland]

Do you have a source for that? Dropping that age limit from 15 to 12 years would obsolete about 20% of the fleet overnight, since the age spread of the cabs is fairly linear.

[tialaramex]

https://tfl.gov.uk/info-for/taxis-and-private-hire/emissions...

So it isn't overnight, it's gradual, it will accelerate fleet replacement significantly, but not 20% of the fleet overnight.