That might be true in counties like Surrey, Lancashire or Hampshire, but I'm not so sure about rather more 'puritan' police forces like Essex, Strathclyde or Thames Valley.
My limited experience of Police forces (or maybe it is less limited than it should be...)
Durham Police - 1987. 93mph in my brand new Nova (I had just run it in and was giving it its first taste of 70+). Threatened with court appearance, reduced to fixed penalty after I wet my pants (figuratively - just want to be clear). I was only 17 at the time.
Northumbria Police - 70 in a 50. "Hello, how are you, do you know why we've stopped you?' 'Absolutely, I was speeding.' 'Well you got that right for starters. Just take it easy, the roads are a bit wet'. And off I go with a warning...???!!!
I got let off about 3 times after that. Started to wonder if I had some sort of freemason's logo inadvertently stuck to my bumper or something.
Met Police 1995 - unfortunately (for me) I undertook an unmarked car in the Limehouse Link - pulled for 40 something in a 30 but I think I really annoyed him with my smart manouevre. I was late for my concert at the Royal Albert Hall as a result. Not happy!
Wiltshire - 1997 - 103mph. "[Grin] Got absolutely no problem with how you were driving mate but you were doing over 100... Keep it down to 85 next time. But make sure you get a lift to court because you won't be driving home [laughs]." Thanks for the tip! Anyway the happy outcome was that the excellent British magistrates had sympathy and I kept my licence! Started to check my clothing for inadvertent freemasons logos too.
Birmingham - an excellent old-timer pulled me over after having tailed me for miles on the M6 in his unmarked BMW. Doing 85-100mph - he expressed great dislike for Jack Straw who was Home Sec at the time and told me to keep the speed down. No ticket, nothing. Really starting to wonder now.
Kent - need to be going seriously fast to get them interested. Never even seen a flicker of interest from any Kent car.
What do I take out of this? I have found the great British policeman to be very fair-minded and willing to take a liberal line if your driving is safe and roads are clear. Just don't annoy them by silly manoeuvres; speak politely and respectfully; and more times than not you will drive off with a warning.
And last but not least Cheadle - just got GATSOed at 36mph on a two lane 30mph stretch shortly before midnight. I am sure you will all be pleased to hear that I am now off to a speed awareness course in April. Looking forward to it!