Unregistered land in English law is land that has not been registered with HM Land Registry. In unregistered land proof of title is based upon historical title deeds.

It is in the interests of the land owner to register their land, largely due to provisions within the Land Registration Act 2002

Land Registration Act 2002

The Land Registration Act 2002 is an Act of the Parliament of the United Kingdom which repealed and replaced previous legislation governing land registration, in particular the Land Registration Act 1925, which governed an earlier, though similar, system...

affording the land owner greater protection against adverse possession.