Most standard car insurance policy's will NOT cover you for track days and it is worth checking if taking your car on track days invalidates your insurance policy.

There are however insurance companies who will insure your vehicle on track days and you can expect to pay around £100 (obviously it does change depending on the value of the car, you will also likely have a high excess in case of accidents so you could maybe expect the excess to be £1000-£1500, again this depends on the value of the car.

This may sound high but remember accidents on track days are pretty rare and you are not there to crash, you want to be able to take your car off the track in one piece.
Many people do not bother with getting track day insurance and this is fine if you are comfortable with the fact that if you do have an accident or right the vehicle off you will have to pay everything out of your own pocket.

For drivers who like to do a number of track days throughout the year it is also worth looking at getting year long track day insurance, this can work out cheaper in the long run if you are going to be taking your car on track a number of times.

To reduce the risk of any problems on your track day you should make sure you do track day preparation to reduce the risk of any problems.

Companies offering Track Day Insurance
Moris

Competition Car Insurance