Upvote:3
To drive legally in the UK you need at least "third party" insurance (insurance that covers liability to third parties). Other common types of insurance are "third party, fire and theft" (which covers third party liability, fire damage and theft but does not cover damage to your own car in an accident) and "comprehensive" (which does cover damage to your own car in an accident).
Afaict it's down to the individual insurance companies whether they will cover people on foreign licenses and how much they will charge for doing so.
If you rent a car then usually the rental company will arrange insurance (but do check).
If you want to drive a friends/employers/clients car then the first thing to look into is the existing policy on the car. An employers fleet policy may or may not already cover you, for a personal policy this is unlikely. If the policy doesn't automatically cover you then you should get the policyholder to enquire about adding you. Adding you to an existing policy is likely to be much cheaper than getting a seperate policy just for you.
If you brought your car with you on a visit (unlikely if you are from india) then the normal method would be to get coverage for driving in the UK (and all the other countries you need to pass through on the way here) added to your policy back home. Also it's at customs discretion whether or not to admit your car.
If you buy a car in the UK then you would have to get a new insurance policy for it.
http://www.uswitch.com/car-insurance/driving-in-the-uk-on-a-non-uk-licence/
http://www.uswitch.com/car-insurance/car-insurance-for-temporary-imports-non-uk-residents/