Roger Scully looks at the results of the latest Welsh Political Barometer Poll.

Theresa May has helped lift support for the Conservative party in Wales to its highest level for six years. This is the stand-out finding from the latest Welsh Political Barometer poll, the first opinion poll to be conducted in Wales since the change of Prime Minister.

As usual, our poll asked people how they would vote both in a general election for the House of Commons and also in an election for the National Assembly. First, Westminster. Here are the figures from our new poll (with changes from the last Barometer poll, conducted in early July, indicated in brackets):

Labour 35% (+1)

Conservative 29% (+6)

Plaid Cymru 13% (-3)

UKIP 14% (-2)

Liberal Democrats 7% (-1)

Others 2% (-1)

For the second successive time, our Barometer poll sees a big change in the support level of one of the main parties. Last time around it was Labour seeing a five-point fall – from which they have only recovered a single point in our new poll. Now we see a big boost for the Conservatives, under their new UK leader. The last time that the Welsh Tories scored this highly in a Welsh poll for Westminster was October 2010.

Meanwhile, after getting their best-ever Westminster figure from YouGov in July, Plaid Cymru unsurprisingly slip back three points; UKIP decline a couple of points, on top of an identical decline in our previous poll.

If we take the changes to party support since the May 2015 general election implied by this poll, and apply them uniformly across Wales on the current seat boundaries, we get the following projected result (with all seats won by a party at last year’s general election remaining in their hands unless stated otherwise):

Labour: 24 seats (losing Ynys Môn)

Conservative: 11 seats (no change)

Plaid Cymru: 4 seats (gaining Ynys Môn)

Liberal Democrats: 1 seat (no change)

What about the new electoral map for Wales proposed by the Boundary Commission just a couple of weeks ago? Under those boundaries – and using the ‘notional’ 2015 results for those boundaries produced by Anthony Wells of YouGov – this poll projects the following outcome:

Labour: 15 seats

Conservative: 10 seats

Plaid Cymru: 3 seats

Liberal Democrats: 1 seat

These projected results would represent a net loss for Labour of three seats from the 18 that Wells projects them, on the new boundaries, to have won in 2015. The Cardiff North, Flint & Rhuddlan, and Wrexham Maelor seats, all projected by Wells to have been narrowly won by Labour on the new boundaries, would on the figures in our new poll now be won narrowly by the Conservatives. Labour would still be projected to win a majority of Welsh seats but only barely so – 15 out of 29.

What about for the National Assembly? I’ll start as per usual with the constituency vote. Here are the findings from our poll (with changes from the last Barometer poll once again indicated in brackets):

Labour 34% (+2)

Conservative 24% (+5)

Plaid Cymru 20% (-3)

UKIP 13% (-3)

Liberal Democrats 6% (-1)

Others 3% (no change)

We continue to see the Labour party some way in the lead. But once again, the big change in this poll is a large leap in support for the Welsh Conservatives. And as with Westminster, we see support for both Plaid Cymru and UKIP ebbing since our July poll.

If the changes from May’s Assembly election indicated by this poll are applied uniformly across Wales, then only two constituency seats are projected to change hands, both gained by the Conservatives from Labour: Vale of Glamorgan and Vale of Clwyd.

The findings for the Assembly regional vote show a broadly similar picture:

Labour 29% (no change)

Conservative 22% (+4)

Plaid Cymru 21% (-3)

UKIP 13% (-2)

Liberal Democrats 6% (no change)

Others 10% (no change)

Applying once more the assumption of uniform national swing, and also taking into account the projected constituency results just mentioned, our poll provides the following projected outcome for the regional list seats:

North Wales: 2 UKIP, 1 Conservative, 1 Plaid

Mid & West Wales: 1 Labour, 1 UKIP, 1 Plaid, 1 Conservative

South Wales West: 2 Conservative, 1 Plaid, 1 UKIP

South Wales Central: 2 Plaid, 1 Conservative, 1 UKIP

South Wales East: 2 UKIP, 1 Conservative, 1 Plaid

This, in turn, gives us the following overall projected outcome:

Labour 26 seats (25 constituency, 1 regional)

Conservative 14 seats (8 constituency, 6 regional)

Plaid Cymru 12 seats (6 constituency, 6 regional)

UKIP 7 seats (7 regional)

Liberal Democrats 1 seat (1 constituency)

Overall, this new poll shows a significant lift in the fortunes of the Conservative party. This confirms that the broad picture indicated in recent Britain-wide polls applies in full to Wales as well. It is not at all unusual for new Prime Ministers, or leaders of major parties to enjoy something of a honeymoon period. In our September Welsh Political Barometer Poll last year, the recent leadership victory of Jeremy Corbyn appeared to give his party an immediate boost in the polls. The ‘Corbyn Bounce’ was very short-lived: by the time of the next poll, in December, it had already disappeared. The fact that our new poll has been conducted some weeks after Theresa May’s accession to 10 Downing Street suggests that the boost received by the Conservative party could be a little more enduring. But as she will doubtless be aware, and supporters of her party should bear in mind, all Prime Ministerial honeymoon periods come to an end eventually.

The poll, for ITV-Cymru Wales and Cardiff University’s Wales Governance Centre, had a sample of 1001 Welsh adults and was carried out by YouGov from 18-21 September 2016.

Postscript: And, for the cognoscenti/confirmed saddos, here are the Ratio Swing seat projections from the poll.

For Westminster, Ratio Swing projects the exact same seat outcomes as UNS. Ynys Môn is the only seat projected to change hands on the existing boundaries, while the Conservatives would narrowly make some gains on the notional new boundaries.

For the National Assembly, Ratio Swing also projects the same constituency results, with the Conservatives gaining Vale of Glamorgan and Vale of Clwyd.

Taking these constituency ‘results’ into account, Ratio Swing then projects the following outcome for the regional list seats.

North Wales: 2 UKIP, 1 Conservative, 1 Plaid

Mid & West Wales: 1 Labour, 1 UKIP, 1 Plaid, 1 Conservative

South Wales West: 2 Conservative, 1 Plaid, 1 UKIP

South Wales Central: 2 Plaid, 1 Conservative, 1 UKIP

South Wales East: 2 UKIP, 1 Conservative, 1 Plaid

In short, as with the constituencies, these are exactly the same regional results as projected by uniform swing! (That was really worth doing, wasn’t it…)