PERHAPS they thought detection was unlikely, since nothing could keep up with their litre sports bikes.

In which case they didn't count on the police having an unmarked 170hp Honda VFR1200F.

Video released by the Norfolk Constabulary shows the police motorcycle reaching over 150mph while chasing the five sports bike riders on the A47 at Trowse, near Norwich, on August 6 last year. The force says their speed was recorded at 140mph 'by means of a follow check in a calibrated police vehicle'.

The video shows the police officer working through the pack and pulling alongside the lead rider, who is still blithely going about 100mph, before shouting "Pull over!" Bet the BMW S1000RR rider got a sinking feeling then.

The five are due to face a disqualification court hearing in June.

Chief Inspector Kris Barnard, head of the joint Norfolk and Suffolk Roads Policing Unit, said: "All too often officers have to deal with the results of drivers speeding, which can be devastating, with families and friends being left behind to pick up their lives after the event. One fatality on our roads is one too many.

"Speed limits are in place for a reason – the limit is set at the maximum safe speed to travel on a particular stretch of road."