Hundreds of drivers convicted for not updating their driver's licence photo ID may have been incorrectly prosecuted, a Lincoln solicitor says.
Michael Pace recently won a case by arguing the wrong section of the Road Traffic Act 2010 was used.
He said points may have been added to licences and insurance invalidated, as a result of the error.
Lincolnshire Police said it was "of concern" that motorists might have been dealt with incorrectly.
Ch Insp Stewart Brinn said: "We have issued clear guidance to all our staff to rectify this situation and we have also raised the issue at both regional and national forums."
Mr Pace, an ex-traffic policeman and specialist in traffic law, said Section 87.1 of the act deals with driving without a valid licence, but Section 99 deals with updating information such as the photo ID, which must be done every 10 years.
Under Section 99, a fine of £1,000 can be imposed but points cannot be levied, vehicles cannot be seized and the offence does not affect the validity of the licence or insurance.
Keith Peat, of the Association of British Drivers, said: "Points on licence can mean loss of job… it is an enormous story to emerge… an enormous mistake and it is obviously going to have to be corrected."
Mr Pace added: "It is hundreds if not thousands of people who have been wrongly convicted around the country.
"That has to be a major issue - courts have not realised it is the wrong offence, the prosecutor has not realised it is the wrong offence, they have pleaded guilty and gone away thinking that justice has had its day when in fact it is a big injustice that has occurred here."
Motorists can appeal to the court and ask for fines and solicitor's costs to be returned if they think they have been wrongly convicted, he added.
Ch Insp Brinn said: "The confusion has arisen as a result of the particular act and section which has been deemed to be breached.
"I can only reinforce that failure to have a current photograph or address on a driving licence remains an offence for which people can face prosecution."