I suggest you go read the Road Traffic Act.
I've quoted the relevant bit above ;)
If I were feeling a bit malicious, I'd query how lawful authority can be given to permit an act which is otherwise unlawful.
Having been closely involved with a case that was has been through the High Court and the Court of Appeal recently, a similar issue arose, ie can someone give authority to sanction an act which is otherwise unlawful?
There is no
specific exception to suggest that a landowner can give lawful authority for a third party (or indeed themself!) to drive on such land, so where does the authority arise from?
As far as I am aware, there is no specific clause which allows landowners to drive over their own land; and permit others to do so. There is thus a 'chicken and egg' situation which could exist between the landowners' rights and the provisions of Section 32 of the RTA.
Either way, Section 32 suggests that unless the landowner has given permission, then it is an offence under the RTA to drive on the track - and that would, I presume, be a criminal offence and not a civil offence.
Hello again darkness, my old friend...