Hello Smiley,
There isn't a simple answer to your question, but here are several points to consider.
You need the permission of the land owner to take a vehicle onto their land. without such permission, you could be trespassing as the vehicle will damage the land.
You must conform to what the land owner permits you to do.
Even some private land is subject to council by-laws covering the use of the land, or even some codicils put in place by previous owners can place restrictions on how land can be used.
Neighbours or other nearby properties may have courts restriction orders in force against the land owner preventing some types of activity.
Some private land adjoining highways can be subject to some highway regulations, such as the need for a car to be taxed, mot'd and insured, and the driver to be licenced and fit to drive.
If you intend to use your normal day to day road car, you MUST read the terms and conditions of your insurance policy, as most policies exclude liability if the car is used for racing or similar performance based sports activities. Be warned if you do use your car for such activities it may VOID your policy, which has far reaching implications when trying to renew or arranging new insurance of any type as you have to declare if you have been declined or had an insurance policy voided.
Again depending on the T&Cs of your policy you may be personally liable for any damage to your vehicle and damage to any third party persons vehicles or property.