The calamitous news for Theresa May comes from the first seat by seat projection for the campaign, and suggests the Conservatives will fall 16 seats short of an overall majority. The polling method has taken into account an unusual technique using a complex computer model.
The YouGov prediction would leave Theresa May with 310 MPs – 20 fewer than at the time of dissolution of the last Parliament – while Labour are set to surge from 229 to 257 MPs on June 8 election, a gain of 28 seats in the Commons.
The shocking scenario could leave Theresa May’s hand weakened ahead of Brexit negotiations – or see her ousted by an opposing coalition government.
Theresa May struggled to pass controversial bills, including changing rules on tax credits, with a 17 seat majority before calling the election.
Experts have branded the rogue poll 'utter tripe' and instantly cast doubt on the model. It contradicts every single other poll conducted over the past two years.
Sterling took at hit in early trading today after the publication of the poll and fears grow of a hung parliament.
Nomura's Jordan Rochester said: "GBP is lower this morning and rightly so as there continues to be polling news that suggests a hung parliament is possible if the trend continues.
"GBP/USD has traded below 1.2800 early in the session, and EUR/GBP back above 0.7820. The move was driven by YouGov’s first constituency-by-constituency estimate of the election that predicts that the Conservative party would obtain 310 seats (down from the current 330) and fall short of an overall majority (by 16 seats), leading to a hung parliament."
This afternoon it began to make back the losses it had suffered.
The shocking scenario could leave Theresa May’s hand weakened ahead of Brexit negotiations
The former Home Secretary called the General Election when her party was 22 points ahead of Labour, however her lead has been slimmed down in a number of polls to just single digits within the space of a few weeks.
The projection, which was carried out for The Times, was based on a complex model and sampled 50,000 people over the course of seven days.
James Morris, who was Ed Miliband's pollster, added: "At the last election YouGov seat-based model had Labour sauntering home. No doubt they've tweaked it but, well, this is rather brave."
Pollsters have struggled to gain back trust following incorrect predictions in the last UK General Election, the EU referendum and the US presidential run.
But insiders have reassured politicos and bookies they have fixed many of the kinks which led them to get the results of major votes so wrong in previous years.
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Snap election 2017: The pictures politicians may not want you to see Sat, May 27, 2017
Protests, fights and daleks, it's all happening as the politicians hit the campaign trail for the snap election
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Jeremy Corbyn during a visit to Hackney Marshes Football Pitches, to highlight Labour's manifesto commitment to ensure 5% of the Premier League's television rights income is diverted to the grassroots game, during a General Election campaign
Pollsters have struggled to gain back trust following incorrect predictions in the last UK election
However some are refusing to accept the prediction – including former Labour leader Ed Miliband, who was expected to win all-out victory in the 2015 vote.
He tweeted: “The pollsters have been off my Christmas card list since 2015. #justsaying.”
LBC radio host Iain Dale added: “Am I alone in thinking that YouGov are going to look complete and utter prunes on June 9th?
“The alternative is that I will…”
Asked about the poll results today in Plymouth, Mrs May said: "The only poll that matters is the one that's going to take place on June 8 and then people will have a choice as to who they want to see as leader."
Theresa May struggled to pass controversial bills with a 17 seat majority before calling for a vote
It comes as Theresa May warned only she can make a success of Brexit – claiming Jeremy Corbyn would be “alone and naked” in crucial negotiations.
In her most ferocious assault yet on her Labour opponent, she pleaded with voters not to “sleepwalk” into giving him the keys to Downing Street as head of a chaotic minority Government propped up by anti-Brexit parties.
Her comments will have doubly stung for Jeremy Corbyn – as they referenced a famous quote from Labour hero and NHS founder Aneurin Bevan.
She said: “Jeremy Corbyn’s minders can put him in a smart blue suit for an interview with Jeremy Paxman but with his position on Brexit he will find himself alone and naked in the negotiating chamber with the EU.
“Now I know that’s an image that doesn’t bear thinking about… but actually this is very serious.”
The Labour leader turned Theresa May's election slogan against her this morning, claiming that after seven years of Conservative-led administrations, the state of health, social care and education were "anything but strong and stable".
Five more years of Tory government would be "disastrous" for public services, while Labour would be willing to ask the richest to pay "a little bit more" to fund them, he said.
Mr Corbyn's decision to go on the attack over public services comes after Mrs May attempted to force the campaign focus onto her core messages of leadership and Brexit, saying the Labour leader was unprepared for crunch Brexit talks within days of the General Election and would find himself "alone and naked" in negotiations.
Labour's analysis claims that under Tory plans, 5.5 million people will find themselves on NHS waiting lists in England by 2022, the scheduled end of the next parliament, a 1.8 million increase from now.
Seeking to exploit perceived Tory weakness on social care, Mr Corbyn also said 1.5 million older and vulnerable people will not have their social care needs met.
YouGov quizzed 50,000 panellists and applied their answers to a computer model which takes into account the fact that voters from similar demographics tend to vote the same way.