Revelations that so many law enforcers, most of whom are still in post, have turned law-breakers were dubbed "deeply worrying" by a road safety campaigner.

The disclosures – made under the Freedom of Information Act – showed that of the four forces in Yorkshire, West Yorkshire had the highest number of serving officers convicted between January 2006 and April 2007.

Fourteen of the convictions were for motoring offences.

The force would not disclose what the other convictions were for, but last year an exclusive Yorkshire Post report prompted outrage when it was revealed 10 of its serving officers had been convicted of assault.

In South Yorkshire seven police officers were convicted of criminal offences – four for traffic offences, one for affray, one for common assault and another for obstructing the police.

Only one resigned prior to disciplinary proceedings. The others have all been allowed to stay in the force despite breaking the law.

Neither force would disclose how many of their officers had received run-of-the-mill speeding fines or penalty points.

In Humberside three officers were convicted of speeding offences and are still in post; another, who was convicted of perverting the course of justice, has since been dismissed.

Across the force area there were a staggering 1,912 occasions where police vehicles activated a speed camera while engaged on duty. Of those, 1,900 were not pro-cessed as it was established that the vehicles were res-ponding to emergency calls. The remaining 12 were cancelled after further inquiries.

The year before there were only eight occasions when Humberside Police officers were caught by speed cameras while on duty. The force said the figure had spiralled so dramatically because of the "increased use of roadside cameras to detect speeding and other offences".

Across the region only North Yorkshire Police officers emerged with a clean slate, although the force did concede that five had been caught speeding and fined.

Last night a spokeswoman for Huddersfield-based road safety charity Brake called the figures "deeply worrying".

"These numbers are terribly high and it is of grave concern that serving police officers who are supposed to be enforcing the law are so blatantly breaking it.

"I think these figures could lead to a lot of mistrust from members of the public. If they can't trust the officers not to be breaking the law then that is a deeply worrying state of affairs."

Last year the Yorkshire Post revealed that more than 40 officers serving in Yorkshire had criminal records or had been cautioned for offences ranging from drink-driving to assault, shoplifting and dangerous driving.

This prompted calls for a more accountable and open system for disciplining those who break the law, but the figures released this year were even less clear in some cases.

West Yorkshire Police did not give any details of the offences committed by its 20 law-breaking officers, apart from the fact that 14 of them were motoring offences.

A spokesman said: "We expect the highest standards of our officers.

"All cases where officers receive criminal convictions or cautions are subject to close scrutiny on an individual basis to establish whether the convictions or cautions will affect their job and whether there are any disciplinary issues arising that need to be addressed."