In plain English
Previous limits are cancelled — now the default applies: 60 mph on single carriageways and 70 on dual carriageways and motorways, for cars.
Where you'll see it
Leaving towns and villages, where the 30 or 40 zone ends and open road begins.
The common trap
Reading it as "no limit" or "always 70". On a single carriageway it means 60 for a car — and less for vans and anything towing.
Memory anchor
The black stripe crosses out the old limit. What's left is the national default — 60 single, 70 dual.