Update: It seems that most insurance companies have calmed down about this now and will accept that winter tyres are not a modification as long as they are the correct specification/size and are fitted on all four wheels. If in doubt, contact your insurance company for confirmation.
Car insurance companies have a general policy that you must notify them of any modifications of your car from its standard (original) specification.
In most cases, this is a sensible and reasonable precaution. Sometimes your premium will rise as a result, sometimes it won’t.
However, the recent winter weather and growth in popularity of winter tyres has highlighted a problem with the definition of modification, as far as insurers are concerned.
Logically, winter tyres are not a modification to the vehicle and so you should not have to tell your insurer about fitting winter tyres, as long as they are professionally fitted and are the correct specification for your car.
The AA and the Association of British Insurers (ABI) agree with this but say that as a precaution, you should notify your insurance company if you fit winter tyres. Some insurance companies do want to know.
If you are unlucky and speak to someone who claims you have modified your vehicle and that your premium will increase, insist on speaking to a manager. The person you are speaking to is either very ignorant or is working to rules that are seriously misguided.
Winter tyres make a vehicle safer in winter conditions. It does not need to be snowy – at temperatures below 7 degrees, tests have shown that cars fitted with winter tyres can stop quicker than cars fitted with summer tyres.
Remember – winter tyres should be fitted to all four wheels of your car. Fitting winter tyres to two wheels only is potentially dangerous as it will unbalance the handling and grip characteristics of your car and could increase the likelihood of you losing control.