.uk

Overview

• .uk is the country-code top-level domain (ccTLD) for the United Kingdom.
• First registered on 24 July 1985 and delegated to Nominet UK for management.
• Extremely popular in the UK: over 10.5 million registered domains (total registrations: 10,508,932; breakdown: 9,314,572 third-level and 1,374,360 second-level as of January 2024).
• DNSSEC has been in use for .uk since March 2010.
• Domain structure supports both direct second-level registrations (example: example.uk) and traditional third-level registrations beneath established second-level domains (example: example.co.uk).

History

• The ccTLD system was defined by RFC 920 in October 1984 using ISO 3166 two-letter codes. Although the ISO code for the UK was GB, .uk (defined earlier by the JANET naming scheme) was chosen and registered on 24 July 1985.
• Early administration was delegated to individuals and academic networks before being transferred into a formal registry.
• Nominet UK was formed in 1996 as a not-for-profit organisation to operate the .uk namespace and continues as the registry and sponsor.
• Direct registrations under .uk (second-level) were opened on 10 June 2014; a reservation period for holders of existing corresponding third-level domains ran until 06:00 BST on 25 June 2019.
• IANA delegates the .uk zone to Nominet UK.

Usage and Audience

• Common audiences and uses:
  • .co.uk — commercial entities and general business use (the most used second-level domain under .uk).
  • .org.uk — not-for-profit organisations.
  • .me.uk — intended for personal names (since tightened to require natural persons).
  • .ac.uk — higher and further education and research institutions.
  • .sch.uk — primary and secondary schools (allocated at the fourth level under a local-authority label).
  • .gov.uk, .mod.uk, .nhs.uk, .police.uk — government, defence, health and law enforcement bodies (administered separately by relevant authorities).
• There are no broad territorial residency requirements for most .uk registrations; many second-level zones impose their own eligibility conditions.

Registration Rules

• Eligibility and general rules:
  • Any individual or legal person can register under the general .uk namespace (subject to the specific rules of particular second-level domains).
  • Registrations are allocated on a first-come, first-served basis for qualified applicants.
• Second-level domain restrictions and special cases (examples):
  • .ltd.uk — registrant must be a UK private limited company and the domain must correspond to the exact company name as recorded at Companies House.
  • .plc.uk — registrant must be a UK public limited company and the domain must match the registered company name.
  • .net.uk — restricted to ISPs and network companies; not for end-user service provision.
  • .nic.uk — reserved exclusively for Nominet UK.
  • .me.uk — now restricted to natural persons (individuals).
  • .ac.uk, .gov.uk, .mod.uk, .nhs.uk, .police.uk and several others are administered by third-party trustee organisations or government agencies and have stronger controls.
• Character and technical rules:
  • Allowed characters: the 26 unaccented ASCII letters (a–z), digits (0–9), and hyphen.
  • The first or last character of a third-level domain may not be a hyphen.
  • Internationalised Domain Names (IDNs) are not offered by Nominet for the .uk namespace; names beginning with the ACE prefix "xn--" may not be registered.
  • For policy and technical reasons, the character strings "com" and "uk" are not permitted as an SLD or as a third-level label within .co.uk, .me.uk, .org.uk or .net.uk; characters corresponding to an existing second-level domain in .uk are not permitted as third-level labels within those zones.
• Registration channels and pricing (as reported):
  • It is possible to register directly with Nominet UK (example noted: £80+VAT as of 2021), but most registrants use Nominet-accredited registrars where typical retail pricing was around £10+VAT in 2021.

SEO and Brand Impact

• Popularity and trust:
  • .uk is one of the largest top-level domains globally and was ranked among the top five TLDs by registration count in recent years, making it a highly recognised namespace for UK entities.
  • Presence of government, education and institutional second-level domains (.gov.uk, .ac.uk, .nhs.uk, etc.) contributes to a perception of trust and clear namespace segmentation for official organisations.
• Security:
  • DNSSEC deployment since 2010 improves integrity and trust for .uk DNS responses.

Notable Cases or Examples

• Historic and prominent .uk uses include:

  • mod.uk — Ministry of Defence (one of the delegated second-level domains in existence before direct .uk second-level registrations were opened).
  • parliament.uk — Parliament of the United Kingdom.
  • bl.uk and british-library.uk — British Library.
  • nhs.uk — National Health Service organisations and trusts.
  • ukaea.uk — used by the United Kingdom Atomic Energy Authority (operator of JET was noted as an example).
  • royal.uk — used for the British royal family's website; rct.uk — Royal Collection Trust.

• Second-level namespace examples and management:

  • .co.uk, .org.uk, .me.uk, .ltd.uk, .plc.uk, .net.uk and .sch.uk are managed by Nominet UK (with varying eligibility rules), while other SLDs are managed by government or trustee bodies with tighter controls.

% IANA WHOIS server
% for more information on IANA, visit http://www.iana.org
% This query returned 1 object

domain:       UK

organisation: Nominet UK
address:      Minerva House
address:      Edmund Halley Road
address:      Oxford Science Park
address:      Oxford OX4 4DQ
address:      United Kingdom of Great Britain and Northern Ireland (the)

contact:      administrative
name:         TLD Registry Services Management
organisation: Nominet UK
address:      Minerva House
address:      Edmund Halley Road
address:      Oxford Science Park
address:      Oxford OX4 4DQ
address:      United Kingdom of Great Britain and Northern Ireland (the)
phone:        +44 1865 332211
e-mail:       registrymanagement@nominet.uk

contact:      technical
name:         TLD Registry Services Technical
organisation: Nominet UK
address:      Minerva House
address:      Edmund Halley Road
address:      Oxford Science Park
address:      Oxford OX4 4DQ
address:      United Kingdom of Great Britain and Northern Ireland (the)
phone:        +44 1865 332211
e-mail:       registrytechnical@nominet.uk

nserver:      DNS1.NIC.UK 213.248.216.1 2a01:618:400:0:0:0:0:1
nserver:      DNS2.NIC.UK 103.49.80.1 2401:fd80:400:0:0:0:0:1
nserver:      DNS3.NIC.UK 213.248.220.1 2a01:618:404:0:0:0:0:1
nserver:      DNS4.NIC.UK 2401:fd80:404:0:0:0:0:1 43.230.48.1
nserver:      NSA.NIC.UK 156.154.100.3 2001:502:ad09:0:0:0:0:3
nserver:      NSB.NIC.UK 156.154.101.3 2001:502:2eda:0:0:0:0:3
nserver:      NSC.NIC.UK 156.154.102.3 2610:a1:1009:0:0:0:0:3
nserver:      NSD.NIC.UK 156.154.103.3 2610:a1:1010:0:0:0:0:3
ds-rdata:     43876 8 2 a107ed2ac1bd14d924173bc7e827a1153582072394f9272ba37e2353bc659603

whois:        whois.nic.uk

status:       ACTIVE
remarks:      Registration information: http://www.nic.uk/

created:      1985-07-24
changed:      2023-03-07
source:       IANA