This chart shows historical voting intentions in the U.K. from the three main parties since August 1970. Data are from Pippa Norris’s website until August 1970 and the UK Polling Report thereafter, and are the answer to the question “If there were a General Election tomorrow who would you vote for?” [or similar]. Letter markers on the bottom show General Elections; number markers on the parties’ lines show other politically relevant events.

A few things to note regarding the data and its visualisation:

This was my first attempt at using JQuery (and my first use of JavaScript in ~8 years), it’s pretty good! Most of the legwork is done by the Highstock JavaScript library, which is free for non-commerical use and rather nice.