In article ,
Colin Rosenstiel wrote:
I thought there was an injunction against horn use after a certain time.
10:30 pm sounds familiar.

Rule 92 in the highway code (http://www.highway-code.gov.uk/07.htm#92)
says that you shouldn't use your horn between 11:30pm and 7am (with
some sensible exceptions and caveats) & refers to the Road Vehicles
(Construction & Use) Regulations 1986. I can't be bothered to see
if those regulations apply equally to police sirens, although
personally I doubt it.

--
Mike Bristow - really a very good driver