Speed cameras in Kent and Medway could be used to catch motorists using mobile phones or not wearing seat belts.

Kent County Council and Medway Council have now both approved a pilot scheme to be run by the Kent and Medway Safety Camera Partnership which will see mobile cameras used to crack down on offenders.

But those caught on the phone or without a seatbelt will escape a fine.

Instead, they will receive a warning letter, alerting them to the fact they have been captured on camera and told why it is dangerous.

That has led to criticism from some county councillors.

The partnership says using speed cameras to tackle offences other than speeding is legally allowed and believe the initiative will improve road safety.

If the trial is successful, it could be extended across the county but will initially be limited to the use of a mobile camera used in Medway.

According to a survey, about one in ten of all drivers in the county take to the road without their seatbelts on – a figure described in a report presented to a meeting of KCC’s highways board outlining the plan as "alarmingly high".

Chris Rogers, of the Kent and Medway Safety Camera Partnership, said: "For every hundred people, ten may not be wearing their seatbelts. We cannot tolerate that and it is unacceptable. We hope a letter will be enough to send out a message that we will not tolerate people either using a phone or driving without a seatbelt."

There was no issue relating to the legality of using speed cameras for other purposes, he added.

"We have talked to the Association of Chief Police Officers (ACPO) and they are happy that it is permissible and does not require special authorisation," he said.

But some county councillors have expressed disquiet that offenders will escape prosecution.

Cllr Elizabeth Tweed (Con), a member of KCC’s Highways Board, said: "I cannot see why these people cannot be fined. They have got to be stopped."

The pilot is expected to get under way this Autumn and will be reviewed after about a year.