Good sources for UK internet statistics

Not for the first time, someone has asked me for a list of good websites for statistics on the UK internet audience and market. So, having pulled a list together, I thought I’d offer it to the wider world. If anyone knows of any sources I’ve missed or forgotten, feel free to comment.
Internet Advertising Bureau
The ‘trade body’ for online advertising in the UK, with lots of numbers about online audience, advertising spend, ecommerce, etc. Probably the best single resource you’ll find.
Heather Hopkins
Heather is the chief UK researcher at a company called Hitwise, which gathers up data from all the big UK internet service providers, and produces some of the most detailed stats anywhere. Hitwise is a paid-for service, but Heather regularly posts some very interesting stuff on her blog.
ABC Electronic
Publish fully audited usage data for various high-profile websites. Very heavy stuff, but often useful for the odd anecdote, as it quotes famous sites like the BBC, Guardian, Yahoo. Click on the link ‘ABCE Data’ at the top of the screen; then ‘Search ABCE Database’; and just press the ‘Search’ button. (If you don’t put anything into the form, it will spit out a complete list of everything it’s got.)
UK Association of Online Publishers
‘Champions the interests of approximately 160 publishing companies.’ Most of their website is members-only, but you’ll find a few interesting (and free) items on this page of ‘research’.
National Statistics
Government stats agency compiles figures on internet use. Especially good to show the growth of broadband.
Statsaholic (formerly Alexaholic)
A great site for generating graphs of the traffic for (almost) any major website in the world. Uses the same data as, but looks prettier. The Alexa numbers must be treated cautiously, as they are only a snapshot of the overall internet population, and probably not a very representative snapshot. But in my experience, the shape of the graph is usually pretty accurate.
Nominet UK domain names
Monthly numbers on the registration of .uk domains, going right back to August 1996. You might also be interested in Verisign’s equivalent data for .com and .net, published quarterly (ish).
… and my perennial favourite…
Overture Keyword Assistant
How many people searched Yahoo (etc) for a particular keyword last month… and what phrases did they use it in? Granted, Yahoo’s a very distant second to Google, but Google doesn’t publish its numbers, and the proportions are probably the same (ish). This site has been a bit temperamental of late, but it’s still running.