What if this were repeated at a general election?
Rather than look at how each party's vote has changed, look at how votes have moved between parties.
Labour would gain 105 seats from the Conservatives, 33 from the Liberal Democrats and 1 from the Greens - a net gain of 139.
The Conservatives would gain 23 seats from the Liberal Democrats, while losing 105 to Labour and 1 to Independent Community & Health Concern - a net loss of 83.
The Liberal Democrats would lose 33 seats to Labour, 23 to the Conservatives and 1 to Plaid Cymru - a net loss of 57.
Plaid Cymru would gain 1 seat from the Liberal Democrats.
Independent Community & Health Concern would gain 1 seat from the Conservatives.
The Greens would lose 1 seat to Labour.
This gives an election result of:
At the May 2010 general election, UKIP set the record for the highest share of the vote for a party which didn't win any seats. On this opinion poll it will dramatically break that record!
And the Liberal Democrats would achieve the second highest ever share of the vote for a party which didn't win any seats.
This would create a bizarre result. We are used to the idea that First Past The Post can leave people feeling unrepresented, but this has usually meant constituents having an MP from a party they didn't vote for, or a party getting a small number of seats compared to its share of the vote.
But this would be different. UKIP, the Liberal Democrats and the Greens would between them command around a quarter of the vote- but not have a single MP between them.
Among the current Cabinet, the Liberal Democrats would naturally all lose their seats. Lord President of the Council Nick Clegg would lose Sheffield Hallam to Labour; Business & Innovation Secretary Vince Cable would lose Twickenham to Labour; Energy & Climate Change Secretary Ed Davey would lose Kingston & Surbiton to the Conservatives; Scottish Secretary Michael Moore would lose Berwickshire, Roxburgh & Selkirk to Labour; and Chief Secretary to the Treasury Danny Alexander would lose Inverness, Nairn, Badenoch & Strathspey to Labour.
The only Conservative Cabinet casualty would be Welsh Secretary David Jones, losing Clwyd West narrowly to Labour (this would be the second closest Labour/Conservative marginal).
In Scotland, of course, Moore and Alexander would not be the only Liberal Democrats to lose their seats. Indeedn all 11 Liberal Democrats representing Scottish seats - as well as Minister for Scotland, David Mundell, who is Conservative MP for Dumfriesshire, Clydesdale & Tweeddale - would lose to Labour, leading Scotland to have 53 Labour MPs and 6 Scottish National Party ones.
The Welsh story is a bit different. The Liberal Democrats would lose their 3 seats to different parties- Brecon & Radnorshire to the Conservatives, Cardiff Central to Labour, and Ceredigion to Plaid Cymru.
Jones would be the most senior Welsh Conservative to be defeated, but not the only one. Aberconwy, Cardiff North, Carmarthen West & South Pembrokeshire,Preseli Pembrokeshire and Vale of Glamorgan would all fall to Labour, giving Labour 33 seats, Plaid Cymru 4 and the Conservatives 3.
The highest Liberal Democrat share of the vote would be in Orkney & Shetland, where they would be in second place (Labour winning the seat for the first time, and the first time since the July 1945 general election that a non-Liberal candidate won) with 25.49% of the vote. The only other seat where the Liberal Democrats would get over a quarter of the votes is Westmorland & Lonsdale, where the Conservatives would win, with Labour second and the Liberal Democrats third on 25.12%.
However, the top target seats would be:
The Liberal Democrat problem is obvious. On that opinion poll, they are looking at obliteration. Not only that, but their top targets are generally seats where they are third (or even fourth).
UKIP would have 500 seats where they get over 10% of the vote, and in 39 of those they would get over 20%. The highest share of the vote is 23.87% in Christchurch.
However, the targets which they would win with a swing of less than 5% are:
Something is obvious here. It seems that UKIP target seats would also be Liberal Democrat ones, and indeed, in every seat where UKIP needs a swing of less than 10% to win, the Liberal Democrats also need a swing of less than 10%.
While on the subject of UKIP target seats, one of the most interesting is Aberdeenshire West & Kincardine, which would be a Labour seat. UKIP would need a swing of 8.62% swing to win it from Labour, but would have to leapfrog the second-placed Conservatives, the third-placed Scottish National Party and the fourth-placed Liberal Democrats. This would be the seat with the smallest gap between the first and fifth parties.
For the Greens, there are only 3 seats where they would get over 10% of the vote:
There are things to note. Firstly, this is a middle of the mid-term poll.
Seocndly, shifts in votes are consistent, and every seat will buck the trend in one way or another (although the poll indicates a Liberal Democrat wipe-out there would be some who would buck the trend). This creates an element of volatility - a small bucking of the trend can change who the winner is, and with this repeated across loads of seats, any result is going to be a surprise.
Thirdly, and connected with this, there will be a rise in three- or four-way marginals. And there is the potential for some seats to be ones where during the election campaign you cannot be sure which one of five parties is going to win it. The first genuine five-way marginal cannot be too far away.
Fourthly, we should expect more seats to be won on a majority, but not a plurality, of votes.
Fifthly, the overall result will be less proportional.