I made this site because I couldn't find an up-to-date source for council compositions with accessible data.
I've made the site and the CSV databases Public Domain (download links above), using a Creative Commons license.
Lots of information sources on councils will use the term "No Overall Control". I consider this to be journalistic code for either "Not yet decided" or "We couldn't be bothered to check". In reality many councils are run by a coalition of parties, so although I've kept references to NOC where there's no majority, I've also added the coalition in control (if I can be bothered to check, of course). In the table on the front page, NOC council control is based on the party of the mayor or the largest coalition party.
If you find this site useful or have ideas for how it could be used for the public good, my email link is at the top.