As far as I know not, unless they're in unmarked cars and trying to lure you into speeding so they can nick, yes N. Wales Police I knew who you were!!!
I always thought that it depends on driver training. Your basic bobby in a panda car isn't supposedly allowed to break speed limits, whereas your traffic copper with advanced/pursuit training is in certain situations.
Similarly, a friend that used to be a paramedic told me that ambulances are not allowed to break limits, and any accident caused by them jumping red lights/overtaking etc. can be seen as their responsibility.
