Only 354 of 90,000 police caught on camera speeding or jumping red lights last year were punished.
Last night forces were accused of double standards after it emerged that only one in 200 officers was fined or given points, compared with 84 per cent of ordinary drivers.
In a quarter of the cases the police cars had their blue lights flashing, suggesting officers were attending an emergency.
However, nearly all of the rest had the slate wiped clean by senior police, saving them from three points on their licence and a £60 fine.
Managers have the discretion to cancel tickets if an officer can persuade them they had a good reason for speeding, such as pursuing a suspect or trying to find a witness.
But critics point out motorists enjoy no such rights and that if they want to challenge a fixed penalty notice they must go to court.
They also say the disparity between the figures raises the suspicion that thousands of officers are being let off even if they do not have a valid excuse for speeding.
Dianne Ferreira, spokesman for road safety charity Brake, said: "Police officers should not be speeding in the first place.
"They should be setting an example and they should have to face the force of the law like everybody else when they break the rules."