When a car is stolen , the registration number of the stolen car , is added to police data base and DVLA.  But when you go to DVLA, when you are checking the Road Tax or MOT for a suspicion stolen car, you don’t see the Word ‘Stolen’. You only see the expire date for Tax and Mot of a stolen car.  But there is no indication that the car you are checking is stolen unless you pay to some of the websites to check it for you.  If a member of public is thinking a car is stolen, the best and quickest way to help police , should be to check the suspicious car Road Tax. The reason the car theft is high is because there is no info available to member of public to check if a car is stolen by checking its Road Tax.