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Car Advice · Owning a car

Car Insurance Explained: What Affects Your Premium

By the GT Automotive team · 11 October 2026 · 2 min read

Front of a used car at GT Automotive, Sheffield

Insurance can be one of the biggest costs of running a car, and it’s the one people most often forget to check before they buy. Here’s how it works, and what you can do about the price.

The three levels of cover

  • Third party only: covers damage you cause to other people and their property, but not your own car
  • Third party, fire and theft: the same, plus your car if it’s stolen or catches fire
  • Comprehensive: also covers damage to your own car, even if the accident was your fault

Comprehensive isn’t always the most expensive. It’s worth getting quotes for all three.

Insurance groups

Every car is placed in an insurance group from 1 to 50. The lower the group, the cheaper it usually is to insure. Two similar-looking cars can sit in very different groups, so check before you buy.

What affects the price

  • The car’s insurance group
  • Your age and driving experience
  • Where you live and where the car’s kept overnight
  • How many miles you do a year
  • What you use it for: social, commuting or business
  • Any claims or convictions
  • The excess you choose

Ways to bring it down

  • Get quotes before you buy the car, not after
  • Pay for the year in one go if you can, as paying monthly often costs more
  • Be accurate about your mileage and how you use the car
  • Consider a higher voluntary excess, as long as you could afford to pay it
  • Never put yourself down as the main driver of a car someone else mostly drives. It’s called fronting, it’s fraud, and it can make the policy worthless

Driving away a car you’ve just bought

You need insurance before you drive it, even off the forecourt. Don’t assume your current policy covers you to drive other cars, as most don’t. Most insurers can set up a policy or change your existing one online or over the phone in minutes, so do it before you collect.

How we do it at GT

Tell us which of our cars you’re interested in and we’ll give you the registration, so you can get insurance quotes before you commit.

View our cars →

Quick questions

Do I need insurance to test drive a car?

You need to be insured. Dealers often have cover for test drives, but ask first. For a private sale you’ll normally need your own cover.

Is comprehensive insurance always the most expensive?

No. It sometimes comes out cheaper than third party, so always compare all three.

Do modifications affect my insurance?

Yes. Tell your insurer about any changes from standard, or your cover could be affected.

Find your next car

Ask us for the registration of any car and get your insurance quotes first.

View our carsCall 0114 698 1430