Two computer discs containing names and addresses of 7,685 Northern Ireland motorists have been lost from a sorting centre in Coventry, a leaked letter has revealed.
The information, which was not encrypted, had been sent from Northern Ireland Driver and Vehicle Agency in Coleraine, Co Londonderry, to the Driver and Vehicle Licensing Agency in Swansea.
The leaked letter to Stormont Environment Committee chairman Patsy McGlone stated: "There is no record of the packages leaving this depot in Coventry. In spite of extensive searches at the depot, they have not yet been found."
The agency has written to every vehicle keeper involved. A special helpline has been established and every vehicle record has been marked to alert staff in the "unlikely" event of data misuse.
The data on the discs was being sent to the DVLA in response to requests from a number of vehicle manufacturers, who need to contact drivers about faults or potential faults which had been discovered in certain vehicle models.
Earlier this month it emerged that the DVLA in Wales broke data protection rules when confidential documents were sent to the wrong motorists, it has been claimed.
The agency sent 1,215 questionnaires, including dates of birth and motoring offence records, and about 100 went to the wrong addresses.
The letter said: "This method of sending this type of data has been used without incident for many years. Due to the nature of the data on the discs, encryption was not used.
"The two agencies routinely deal with such 'safety recall' requests and the release of data to manufacturers for this purpose is both lawful and in the best interests of the drivers concerned."
Parcelforce was used for the mail. Vehicle details including registration marks and colours were also included.