Online opinion polls 'may be overestimating support for Brexit'

Online opinion polls in the run-up to May 5 elections across Britain overstated support for the UK Independence Party, suggesting they may also be overestimating backing for leaving the EU, according to a leading polling analyst.

For months, pollsters have been aware of the difference in outcome between online and telephone polling on the question of EU membership.

With the referendum on a so-called Brexit coming on June 23, online polls put the two sides neck-and-neck, while telephone polls have the ‘Remain’ side in the lead.