strange restrictions on temporary speed limit

[GreenV8S]

Happened to see in our local rag that there has been a request for yet another temporary 40/50 mph speed limit between M1 junctions 14 and 15 for roadworks. I was surprised to read that the temporary limit would not apply to police cars, fire engines and ambulances. Not just that they would have their usual exemption in case of emergency, but that the new restriction did not apply to them. This would mean anyone in e.g. a police car can ignore the reduced speed limit at any time! Is this normal?