According to the RAC: “A white circular sign with a single black diagonal stripe through it tells you that the national speed limit applies on the upcoming stretch of road.

“It supersedes any previous speed limit signs you may have had to adhere to, such as passing through temporary roadworks.”

However, the national speed limit depends on the area you are in.

In a built-up area – a road where street lamps are placed no more than 200 yards apart – the speed limit for all vehicles is 30mph. On a single-carriageway, the national speed limit is 60 mph for cars.

However, for vans or vehicles that are towing a trailer/caravan, it is 50 mph.

Similarly, on a dual carriageway and motorway, the speed limit is 70 mph for a car or 60 mph