To get an appropriate range of polls for our averages, we use those conducted by members of the British Polling Council., external
Its members agree to the same rules on transparency, but the council has said membership should not be seen as a guarantee of quality.
The polls we include have come from BMG, Deltapoll, Electoral Calculus, Find Out Now, Focaldata, Ipsos, JL Partners, More in Common, Opinium, Panelbase, People Polling, Redfield and Wilton Strategies, Survation, Techne, Verian (formerly Kantar Public), WeThink (formerly Omnisis), Whitestone Insight and YouGov.
We only include the headline percentages on voting intention, which pollsters calculate by excluding those people who answered “don’t know” or “won’t vote”.
Most of the polls included cover Great Britain, although some do poll the whole of the UK. People surveyed do not get the option to choose parties which only stand in Northern Ireland.
We include data that is in the public domain. Some polling companies will not publish all data for all parties at the same time.