Unadopted land

We have been in a property for 21 years and we have to cross a piece of unadopted land we do not know who the owner of the land is so presumed it was unadopted. There has been no maintenance of the area apart from us occasionally when required. How can we establish ownership of this land.

Nicola - get legal advice first to see if you have a legal claim as to ownership. And then PGs 4 and 5 as appropriate re any application to register such a claim https://www.gov.uk/government/collections/land-registration-practice-guides#guides-1-to-10