Perhaps the single biggest reason for the drop in thefts of newer cars in recent years is the standard fitting of alarms and immobilisers to all new vehicles. Alarms are an effective deterrent to both car theft and theft from your vehicle, and electronic engine immobilisers are highly effective as they prevent the engine from actually starting.
In combination, they are enough to put most car thieves off, and nowadays you can even fit combined alarm and engine immobilising systems to older cars as well.
The Motor Insurance Repair Research Centre (MIRRC), also known as Thatcham, has been testing and approving vehicle security systems since 1992. It publishes a list of approved products and systems, and recommends a category one system which includes it switching on automatically when you leave the car, an "anti-scan" key-code system and a battery backed-up siren.
If you already have an alarm but no immobiliser, don't worry. Engine immobilisers can also be fitted on their own and your alarm can be upgraded to "category one" if it doesn't already meet the Thatcham criteria.
Whilst fitting a Thatcham approved system doesn't guarantee that your car won't be stolen, it will considerably reduce the risk.
It is also important that alarm and engine immobilising systems are fitted properly to your car. The AA recommends installation by a Vehicle Systems Installation Board (VSIB) approved installer such as Automotive Security. Expect to pay around £120 for an engine immobiliser and more for a combined system.
If you already have one or more security device, or you are thinking of securing an older model vehicle it is worth checking your car security rating to see if you meet the necessary standard.

The first documented case of car theft was in 1896, only a decade after gas-powered cars were first introduced. From that early era to today, cars have been a natural target for thieves: They are valuable, reasonably easy to resell and they have a built-in getaway system.
More than a quarter of all recorded crimes are car thefts or thefts from cars, such as stereos and mobile phones. If your car is stolen or broken into, it could mean weeks of expensive inconvenience and the loss of your valuable no claims bonus.
As well as protecting your vehicle, fitting an alarm is a good way to qualify for a cheaper insurance premium. Car alarms are a good criminal deterrent to protect your car and valuables like your stereo. Once activated, the alarm will sound if the car is jolted heavily, if the doors are opened or the windows are smashed. The latest alarms also come with a pager to alert you if they are activated.
