.co.uk

.co.uk is a second-level namespace within the United Kingdom's .uk country-code domain. It is not a separate top-level domain in the DNS root; VYR lists it separately because users commonly register and compare names directly in the .co.uk namespace. Nominet is the registry operator for .uk and directly administers .co.uk.

Nominet's current .UK Registration Policy describes .co.uk as intended for commercial entities and purposes, but marks that intended use as advisory rather than mandatory. In other words, the “co” identity strongly suggests company or commercial use, yet the policy does not impose the kind of eligibility test found in restricted UK namespaces such as .ltd.uk or .net.uk.

For businesses serving the United Kingdom, .co.uk remains a clear way to combine a commercial identity with a UK geographic signal. It can be particularly useful for retailers, service companies and established organizations whose customers expect a British-facing web address. An international company may instead prefer a more globally neutral primary domain and use .co.uk for its UK presence.

Registrants remain subject to Nominet's .UK policies, availability rules, dispute procedures and applicable law. A .co.uk registration does not by itself prove that a business is incorporated in the UK, and trademark or company-name rights should be considered separately.