> The order defines Class M1 vehicles as “those falling within class M1(a) and class M1(b) as specified in Schedule 1 of the Vehicle Classes Regulations, which refers to another bit of UK legislation.
> Oxford’s congestion charge is almost certainly enforced by cameras that scan your number plate. An ox-drawn cart doesn’t have a number plate, so it won’t be charged. Other vehicles like a Renault Twizy or Reliant Robin do have number plates, so they’ll be charged even though they’re technically exempt.
So there's not much to it: Plates are scanned -> the number is checked in the vehicle registration database -> not class M1(a) or class M1(b) -> no charge.
This goes for ox carts, Twizys and Reliant Robins.
But if a vehicle is required to have a number plate, and doesn't (potentially an ox-cart), then you won't be charged for the congestion charge, but you will get charged for something entirely different
I get that the article is light hearted, but given how easy it is to confirm that yes cameras reading number plates is indeed how the system works, I don’t understand taking the time to write that article and not bothering to go further than guessing “almost certainly enforced by cameras that scan your number plate”.