
This type of theft continues to happen weekly in Oxford, so I encourage you to consider fitting anti-tamper screws to your number plates. You can seek advice from your local garage or car dealer. I've just spoken to Motorists Discount Centre (two branches in Oxford). They stock kits of four of these security screws for £3.99 and I think they are really worth fitting if you can. Too many newer cars these days just have the plates stuck on with sticky pads leaving them too easy to remove intact then and use on another vehicle to commit crime that will be traced back to you!
Please check that your number plates are intact on a regular basis, if you do discover that they are missing report to the police immediately via the non-emergency number, 101. You are in a much better position if a crime is reported by someone with a vehicle displaying your plates if you have already reported them stolen! But it's even better to have taken steps to avoid having them stolen in the first place.