Britain was in disbelief last night after an exit poll suggested the Tories were just shy of a majority with 316 seats, defying months of polls suggesting we were on the edge of what would be the closest election in living memory.
Until this point we'd been told the two mains parties - the Tories and Labour - were tied at 33 per cent each, meaning neither would get enough seats to form a majority, and a period of inter-party negotiations inevitable.
Experts are unsure caused this, with some saying that people may have had a last minute change of heart, and others suggesting there could be deeper issues relating to how pollsters gauge the public's voting intentions.
"It could be simply that people lied to the pollsters, that they were shy or that they genuinely had a change of heart on polling day," Alberto Nardelli wrote in the Guardian.
"Or there could be more complicated underlying challenges within the polling industry, due for example to the fact that a diminishing number of people use landlines or that Internet polls are ultimately based on a self-selected sample."
It's led some to ask whether there's a more widespread problem when it comes to accurate polling practices.
Pollsters failed to call Scottish independence referendum when the "no" vote won by 11 points vs. just two to three points had had been predicted.
"If the polls have a poor election, it won’t be the first time," Nate Silver wrote on fivethirtyeight.com. In fact, it’s become harder to find an election in which the polls did all that well."
"Perhaps it’s just been a run of bad luck. But there are lots of reasons to worry about the state of the polling industry."
"Voters are becoming harder to contact, especially on landline telephones. Online polls have become commonplace, but some eschew probability sampling, historically the bedrock of polling methodology."
However Stephan Shakespeare, chief executive of YouGov, took to Twitter to say it had nothing to do with whether voters are interviewed by telephone or over the internet.
Some people are making this into online/offline - ICM, considered the gold-standard phone pollster, had 1% Labour lead— Stephan Shakespeare (@StephanShaxper) May 8, 2015
Phone polls and Online polls last night had identical average errors. This is not about online/offline but polling & voter behaviour— Stephan Shakespeare (@StephanShaxper) May 8, 2015