Thanks for your question.
In order to claim the land as your own
you have to prove what is termed "adverse possession" to the Land Registry in order to have it registered in your name.
If the land in question is unregistered then you must have been using it continuously for 12 years in order to claim possession of it and be registered as the registered proprietor at the Land Registry
If the land is registered then you need only have been using it continuously for 10 years in order to apply for adverse possession at the Land Registry. Notice of the application will be sent to the current registered proprietor of the land, who is obviously at liberty to object. It is therefore more difficult to claim adverse possession of land that is registered.
If you do not know whether the land is registered then you can check using the Land Registry's online service by downloading a copy of the register of the title (if any) for the property:-
If this does not illicit results then you should send a index map search to the Land Registry by using Form SIM (enclosing a map of the area), they will then tell you definitively if it is registered. You can also download that form from the LR website.
In the case of both applications you would have to submit form ADV1 to the Land Registry together with sworn statutory declarations regarding how long you have been using the land (from you and others who know of your use) and it may be something over which you should consider taking specific legal advice from a local solicitor to ensure that the application and supporting documentation is drafted correctly.
It would obviously still be subject to any easements (eg. rights of way) exercised over the land.
If this has been useful please kindly click accept so that I may be rewarded for my time. It will be gratefully received and you will be free to ask follow up questions.