Registered land is land which has at least one Registered Title. It's a term to define an interest in the land, not the physical land itself. This is because the same plot of land may be subject to more than one registered title, a lease over a freehold piece of land for example. Registered Land has boundaries certified to be correct; the title is guaranteed by state insurance. Some land in the UK has no records in Land Registry, this land is considered to be unregistered property.
Compulsory registration came into force in the 1980-1990 or even later in some counties of Scotland. Almost all property transactions in England and Wales and 'sales for a consideration' in Scotland trigger compulsory registration. However if a property has not been sold or charged for long and the owner has not applied for voluntary registration, it may have no records at Land Registry.
To find out if land is registered, perform a search for the Title Register.
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