Spoiler: it isn't. This is made up.
It's heavily paraphrased, but close enough I'd say.
> Every person who shall roll or carry any cask, tub, hoop, or wheel, or any ladder, plank, pole, showboard, or placard, upon any footway, except for the purpose of loading or unloading any cart or carriage, or of crossing the footway:
- https://www.legislation.gov.uk/ukpga/Vict/2-3/47/section/54
The UK has dozens of these ancient laws that were never removed from the books. It doesn't mean they are enforced.
But it's not actually a real law, and cannot be enforced.