.CO.UK is the official UK top level domain. In a country with more than 66 million inhabitants, the .CO.UK domain has a definite role to play in business and administration, and with the help of this domain you will reach just the right doors and the best results. .CO.UK is one of the best-known and most trusted top-level domains with a national designation, and more than 10 million have been registered today. .CO.UK domain can be registered by anyone for up to ten years at a time.