Half of the 8,900-strong fleet of buses operated by Transport for London are already using it, as well as many haulage companies.

Britain’s Transport Research Laboratory (TRL), which helped develop ISA, predicts that 90 per cent of new cars sold in Britain will include ISA as standard.

Dr David Hynd, chief scientist at TRL said: “I personally choose to keep my ISA turned on in my car all the time. It stops me getting speeding fines. It saves me money on my fuel bill, which is always very welcome.

“But, best of all, it provides an extra set of eyes, which I find particularly helpful when I’m navigating new places, or the roads are busy. ISA gives me head space and that makes me a better driver.

“On a motorway, I use ISA in conjunction with cruise control, and have been pleasantly surprised by how much less tired I am after a long journey when using this system.”

TRL admits that sometimes the mapping data can take a while to update when a speed limit has changed, but says it still helps most of the time.

The AA said the technology could be “incredibly beneficial”, particularly when drivers are in urban areas and need to switch between changeable speed limits.