The .ac.uk second level domain is part of the .uk Domain Name System.
.ac.uk is for use by tertiary and other higher education establishments, particularly universities and research establishments.
The .ac.uk is (and has always been) the responsibility of the UK Academic and Education Research Association (UKERNA) - the operators of the academic computer network JANET.
The .uk domain is overseen by Nominet UK.
See also
External site