I found this on Confused.com's website:

Third-party only is the lowest allowable level of car insurance you can get. TPO covers damage to other people and other cars, but any damage to your own car is your responsibility to fund and sort.

Third-party fire and theft (TPF&T)is the same as third-party only, but the insurance will also cover your car if it’s stolen or catches on fire.

Comprehensive car insurance, on the other hand, will cover damage to your car as well.

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You'd be surprised at how often TPF&T premiums are higher than comprehensive. Perhaps it's because the insurer thinks you're asking for that level of cover because you are a high risk driver. Best to see what the difference in premium is in your case. If the comprehensive premium is affordable and not a ridiculous amount more than the TPF&T one, then go with comprehensive for peace of mind. You never know if and when you could make an innocent mistake on the road that could end up costing you a small fortune.

Similarly with the (accident) excess, whether compulsary or voluntary. And lastly, NEVER LIE when getting or using insurance - it could easily lead to your arrest for fraud, cancellation of insurance, and again huge expense if you have an accident (as the policy will likely be cancelled), never mind likely being blacklisted by many insurers or having to pay huge premiums for a long time to come.

That's not the same as where you may have to guess (on estimated annual milage [over estimate, as insurers will likely charge a fee for changing the policy mid-year on top of any change in premium]) or where you may be able to have some leeway (e.g. in how you describe your occupation, as there may be more than one on their list that accurately describes your occupation).

My 15yo Mazda3 is probably worth less than £1k now, but I still go comprehensive (I am lucky enough to have a long time [22 years] no claims) and it only cost me around £185 for this year for 5,000 miles usage. Adding on commuting or work use (not commercial travelling [sales people]) only ever added on about £20 - £30 before, and a similar amount to bump up to 10,000 miles pa.

Try out the screenscrapers to get a wide variety of quotes, but to avoid unwanted sales calls/emails, make sure you only choose those screenscaper websites (or insurers) where you can opt-out of all marketing contact.

Depending on your circumstances - age, driving history, claims

3rd party cover covers damage to other people, car, property etc etc

3rd Party Fire & theft - same 3rd party cover plus car going on fire and if the car or contents are stolen

Comprehensive - same as 3rd Party F&T PLUS damage to your own car, windscreen damage,

The 3rd party cover is the same irrespective.

In my case applying for 3rd party only costs more than comprehensive.

I paid £124 comp with LV last August - 3rd party only was anywhere north of £180