Not sure if anything has changed but this is the up to date guidance given to Traffic Bastard Police regarding speeding ie being pulled over, not fixed or mobile cameras - just for info -
"Guidance for speeding enforcement as of 17/3/11.
These are rules of thumb, so don't take this as a 'given'.
Just gives you an idea from the other side of the fence
30 MPH Speed Limit
31 - 34 mph inclusive – Verbal caution
35 - 42 mph inclusive – Given option of Speed Awareness or Fixed Penalty
43 - 55 mph inclusive – Fixed Penalty
56 mph plus – Court
40 MPH Speed Limit
41 - 45 mph inclusive – Verbal caution
46 - 53 mph inclusive – Given option of Speed Awareness or Fixed Penalty
54 - 65 mph inclusive – Fixed Penalty
66 mph plus – Court
50 MPH Speed Limit
51 - 56 mph inclusive – Verbal caution
57 - 64 mph inclusive – Given option of Speed Awareness or Fixed Penalty
65 - 75 mph inclusive – Fixed Penalty
76 mph plus – Court
60 MPH Speed Limit
61 - 67 mph inclusive – Verbal caution
68 - 75 mph inclusive – Given option of Speed Awareness or Fixed Penalty
76 - 85 mph inclusive – Fixed Penalty
86 mph plus – Court
70 MPH Speed Limit
71 - 78 mph inclusive – Verbal caution
79 - 86 mph inclusive – Given option of Speed Awareness or Fixed Penalty
87 - 95 mph inclusive – Fixed Penalty
96 mph plus – Court"