Every chart on AllPolls.co.uk is drawn from the same measure: the share of the vote a party is credited with in an individual poll, in per cent. Nothing here is a seat projection — a party on 15% may be heading for two seats or two hundred, and this site does not guess which. The archive behind the charts starts in 1943, so the earliest stretches are thin: for the first two decades there is often a single line on screen, because there was often a single firm in the field.
Party and pollster timelines. On a party page — Labour, Reform UK, the Liberal Democrats — each pollster gets its own line, and the horizontal axis is the calendar. Drag the slider under the chart, or scroll the mouse wheel over it, to zoom into a stretch; drag inside the chart to move the window. Hovering anywhere raises a vertical guide with a tooltip naming every pollster at that date and its exact figure: a single published poll shows whole percentage points, while a value the line passes through between two polls is interpolated and shown to one decimal, such as 2.3. Click a name in the legend to hide that pollster's line, which is the quickest way to check whether one firm is carrying an apparent move on its own. With twenty or fewer lines in a chart, each name is printed at the right-hand end of its line, so the legend is optional. Where a firm stops publishing for a long period, its line breaks rather than being stretched across the gap — a run of dormant years should look like absent data, not like a flat opinion.
Election markers and records. The vertical marks are general elections, from 1945 through to July 2024, and the dot on each one is the official vote share, so the last polls of a campaign and the result sit in the same picture. Pins in the chart mark the highest and lowest figures a party has reached, either over the whole archive or within a recent window such as the last five or ten years. On a single pollster's chart the tooltip adds "according to YouGov" (or Opinium, or Survation): a record set in one firm's series belongs to that firm, not to the polling as a whole.
Comparison charts. The comparison view answers a different question — not "what happened in March" but "what did the last three months before polling day look like". Its horizontal axis counts down from 91 days to 0, so the closing stretches of several campaigns lie on top of one another, with older elections drawn more faintly than the most recent. There is no zoom on these; the window is fixed by definition. A pollster page works the other way round: it shows that one firm's most recent poll broken down by party, which answers "what did Opinium find last time out" rather than "how has Labour moved".
Under every chart is a table carrying the same figures as text. It is there as a plain overview, and as the version that still works if the interactive chart cannot load. The home page adds a strip of small charts, one per party, for a quick read of the recent trend across the board. AllPolls.co.uk tracks parties and polling firms only: there are no coalition pages here, and so no majority line on any chart.