Udal law is a Norse-derived legal system, found in Shetland and Orkney in Scotland, and in Manx law in the Isle of Man. It is closely related to Odelsrett; both terms are from Proto-Germanic *Ōþalan, meaning "heritage; inheritance".
Udal law was codified by the Norwegian kings Magnus I and Magnus VI. The Treaty of Perth transferred the Outer Hebrides and Isle of Man to Scots law, while Norse law and rule still applied for Shetland and Orkney.
The courts of Scotland have intermittently acknowledged the supremacy of udal law in property cases up to the present day. Major differences from Scots law include shore ownership rights, important for pipelines and buried cables.
Udal law generally holds sway in Shetland and Orkney, along with Scots law.
Not all land in Shetland and Orkney can be described as falling under udal tenure. The type of tenure depends on how the title arose:
The udal tenant held without charter by uninterrupted possession on payment to the Crown, the kirk, or a grantee from the Crown of a tribute called skat (Norwegian: skatt, now meaning "tax"; cognate with the English term scot, which referred to a similar payment), or without such payment, the latter right being more strictly the udal right. They were convertible into feus at the option of the udallers. Succession law had unique traits, as the eldest son inherited the father's main residence, while the rest of the property was shared among siblings, daughters inheriting half as much as sons.
Several significant aspects of udal law are not seen elsewhere in the UK:
The Abolition of Feudal Tenure etc. (Scotland) Act 2000 extinguished any remaining obligations to pay skat, effective 28 November 2004. In addition, the Land Registration (Scotland) Act 1979 (as amended by the Title Conditions (Scotland) Act 2003) provides that, as of 1 April 2003, first registration will be required on any transfer of an interest in udal tenure that had not previously been entered in the Land Register, as real rights can only be obtained by registration.