LR Practice Guide 5 says that squatters cannot acquire title to land that is subject to public rights of way. That statement has indeed been confirmed by the CA in Smith [2009].

It is important to remember the potentially broad scope of this. Although a highway maintainable at public expense will appear on the public list of streets maintained by the local highways authority, land can be a privately maintainable highway or can acquire highway status by public passage over time. Any such circumstances would almost certainly prevent an adverse possession claim from succeeding. So, if your neighbour owns land over which the public has acquired a right of way, then you cannot claim squatter’s rights over that land. For the authorities see article in [2010] 248 PLJ 2.