A shortcut to this article: opensrs.help/right-to-reserve
In 2014, the .UK registry launched the .UK extension, adding a shorter, sharper TLD to their existing portfolio: CO.UK, .ORG.UK, .ME.UK, .NET.UK, .PLC.UK, and .LTD.UK.
Alongside this launch, the .UK registry implemented a Right to Registration Policy. Under this policy, domain owners who registered a third-level ( .CO.UK, .ORG.UK, etc.) domain before October 29, 2013, may have had the right to register theirs.UK equivalent.
For example, an individual who owned mydomain.co.uk might have had a right to register mydomain.uk.
But since June 25, 2019, all right to reserve expired. Since July 1, 2019, all reserved .UK domains were released for registration, and anyone can purchase the domains.
Currently .UK domain name registration is open for all.