M11 marked police cars - Mapmaker
If I wrote recently that I haven't seen a police car since Easter, then I meant a moving police car. Every time I have been down or up the M11 in the last month or two (from end to end) there has been a parked police car, looking imposing and ominous with its blue & yellow chequerboard livery.

What are they doing? (Apart from causing traffic to do 70mph exactly for the next 2.5 miles, instead of the 76mph it was doing before.) Are they really just looking for a speeding car?

M11 marked police cars - Altea Ego
There are some very nice picturesque picnic spots next to the police parking ramps, along the M11. Cup of tea, corned beef sarnie....
M11 marked police cars - BrianW
Maybe just in position to respond to trouble.
The M11 has some quite long stretches between junctions and a car on a ramp probably has a quicker response time.
M11 marked police cars - smokie
"The M11 has some quite long stretches between junctions and a car on a ramp probably has a quicker response time"

...they also "lurk" rather than driving aorund to save fuel costs...