Thanks for your question.
The land, despite not being ground-level, would still have been owned by someone prior to having been formed at ground level.
In order to claim such land one must prove adverse possession to the Land Registry in order to claim it as their own.
In order to do so a person must enclose the land and look after it for a certain period of time.
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(it may be that the land forms part of one of the registered titles of the properties which it adjoins):-
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. You should do this because the LR will not inform the owner of the land that you have searched against it.
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.
Alternatively, if you do not wish to wait that long then you friend can make an offer to the person who does own it following return of the search results or after having ascertained who the owner of the unregistered land is.
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