My late brother-in-law was a traffic officer here in Wiltshire, and my wife's ex-hubby was also a copper.
Although both were careful not to endorse routine motorway speeding, they both said independently of each other that traffic officers are not especially interested in speed per se, but take a dim view of speed combined with any of the following:-
Poor road conditions / traffic conditions / visibility;
Apparent inattention to surrounding traffic conditions, highlighted by lack of lane discipline, lack of indication, lack of awareness of following traffic;
Any distraction consuming the drivers attention, like mobile phones, putting on make-up, turning to scream at kids in the back, etc;
tail-gating;
Under-taking;
any attempts to intimidate other drivers to move over.
None of the above means that a motorist behaving sensibly at 85 mph on the motorway won't get pulled, but most traffic officers are motoring / car enthusiasts (thats why the majority of them do the job), and only want to catch and deter the idiots.
The above absolutely chimes with my own personal experience - I frequently travel at 90 mph and occasionally (and for short distances) more on motorways, but I drive in accordance with the list of 'dont's' above. I have NEVER been stopped for speed on a motorway.