Nominet, the group in charge of processing .uk domain registrations, said that the landmark had been hit by a pair of businesses. Wokingham-based Nirvana Spa and Pulse 8 Health Club combined to register the Active2011.co.uk domain and become the nine-millionth .uk domain.
Overall, Nominet registered an estimated one million new .uk domains in the past year. The company saw an 11.5 per cent increase in new domain registrations over the past 12 months, up slightly from 11.2 per cent in 2009.
The company has forecast a similar growth rate for 2011 of around 11 per cent.
Overall, Nominet estimates there are some 200 million total domains worldwide, an increase of six per cent over the previous year.
The milestone marks what has been a noteworthy year for the UK domain registry. Earlier this month, Nominet began allowing businesses and webmasters to lay claim to shortened .uk domains associated with their respective trademarks.
In the spring of 2010, the company also moved to improve the security of the .uk domain by instituting the DNSSEC security protocol.