Polls published on the eve of a general election do not have a good pedigree. It’s not just their infamous performance in 1992 that counts against them, though that remains the benchmark for inaccuracy.
Their record at every election in modern times has been patchy at best, and there has only ever been one instance in recent history of a pollster correctly forecasting vote share for each of the three main parties.
Some have come close, however, and this year we’re likely to see a record number of companies publishing eve-of-election polls. Which should we treat with the most credibility?