asked Her Majesty's Government:

Further to the Written Answer by Lord West of Spithead on 10 October (WA 18), whether they will remind the police and other emergency services that the Road Vehicles (Construction and Use) Regulations 1986 do not permit the use of sirens when no other road users are present. [HL80]

I am confident that the emergency services are fully aware of the legal controls on the use of sirens. Individual police forces and other agencies may issue their own guidance, but subject to the law it is a matter for individual drivers of emergency service vehicles to decide when they need to alert to their presence other drivers and pedestrians or others using the road. These drivers are well aware that they should use sirens with restraint, so as not to cause a nuisance to other locals.