- Where the land is unregistered or where the land is registered but the trespasser notched up 12 years adverse possession before 13 October 2003, when the Land Registration Act 2002 came into force, one set of rules will apply - see Land Registry Guide 5
- On the other hand where the land is registered and the trespasser did not acquire 12 years adverse possession prior to that date the provisions of the 2002 Act, which are very different, will apply. Under that Act the trespasser must show 10 years adverse possession in order to apply for registration but there are then extra provisions to be taken into account - see Land Registry Guide 4
However, whichever situation one is looking at, the concept of "adverse possession" is the same, whether under the "old law" or under the newer provisions of the 2002 Act.
The leading case and the starting point when considering the definition of "adverse possession" is JA Pye v Graham (Oxford) Ltd v Graham  UKHL 30. A full explanation of the decision is to be found here.
Other important issues that arise in adverse possession cases can also be found on the other pages in this section of the site - see the contents column on the left.
Cases decided under the Land Registration Act 2002, Schedule 6 are dealt with here.