Like any opinion poll, today's Wales Barometer is not a forecast of what will happen on election day. But it is a snapshot of Welsh public opinion in the days immediately after Theresa May called a snap election. But is it an accurate picture?
Although the headline numbers look, and indeed are, a huge political shock, the underlying movements actually match what's been happening in UK-wide polls.
UKIP support has been falling sharply since January with most of its vote going to the Conservatives. The decrease in Labour’s vote share has been happening steadily over the last five years.
The poll found Labour support would be at similar levels if the election was for the Assembly but with the Conservatives doing less well.
And for the the first trip to the polling stations this year, the local council elections, Labour is still in the lead.
One factor is how voters respond differently when asked to decide who should be in Downing Street. Theresa May is currently the most popular party leader in Wales. On average people like her almost as much as they dislike her, giving her 4.9 out of ten.
The general view of politicians being as it is, getting more than 5 out of ten is generally considered to be beyond reach. But the Prime Minister has nearly managed it, doing even better than what would normally be considered pretty reasonable ratings for Carwyn Jones and Leanne Wood. Theresa May's clear lead over Jeremy Corbyn and Tim Farron explains much.
And calling the election seems to have done her reputation no harm. Our poll suggests that most Welsh people think it was the right decision.
One indication that our poll is broadly accurate is that the almost even split between supporters of remain and leave in the EU referendum is still there, as it has been in every poll since last June, as it was in the polls leading up to the Brexit vote.
The Leave and Remain camps have very different plans about who they'll vote for on election day. 46% of remain voters say they will back Labour, with the Conservatives (20%), Plaid Cymru (15%) and the Liberal Democrats (16%) all far behind.
The secret of the Conservatives' unprecedented lead is with leave voters. 63% plan to vote Tory, just 14% Labour,12% UKIP and 9% Plaid Cymru.(Leave voters who back the Liberal Democrats, like remain voters who back UKIP are very scarce indeed).
So the referendum -and in some cases a period of supporting UKIP- appear to have left some traditional Labour voters ready to vote Conservative. Not that the losses that Labour is facing would be entirely unprecedented.
Many of the seats that the Conservative might win on this polls' figures, such as Delyn, Clwyd South, Bridgend, Newport West and Cardiff West, were won by the Tories in 1983. The Conservatives didn't actually get ahead of Labour in Wales back then as other seats now looking vulnerable, such as Newport East and Cardiff South & Penarth, didn't change hands.
The obvious difference was that the Conservative wins were in seats where there was no incumbent MP with a record to defend. So there is perhaps a glimmer of hope for Labour MPs planning to urge voters to forget about Jeremy Corbyn - and Theresa May- and concentrate on who they want to as a constituency representative.
- The poll, for ITV Cymru Wales and Cardiff University’s Wales Governance Centre, had a sample of 1029 Welsh adults and was carried out by YouGov from 19-21 April 2017.