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The Senedd snake: Which constituencies really matter in Wales’ election?

05 May 2021 4 minute read
Some of the constituencies that will make a difference on election day

Ifan Morgan Jones

With every poll projecting Labour as the largest party, what really matters at tomorrow’s election from the point of view of the composition of the next Welsh government is how many seats Labour win.

If they win by around 27 seats or over they will probably want to give minority government a shot. Anything less than that, 26 or under, and they may be looking for a coalition or at least some kind of long-term deal with Plaid Cymru to prop them up for the next five years.

That is because once Plaid Cymru and the Conservatives, combined, have more seats than Labour in the Senedd it becomes much more difficult for Labour to get any legislation through as they can be overruled quite easily.

Of course, some seats are more under threat than others because of their tight margins.

Behold the Senedd 2021 race in ‘snake’ form – no, infographics aren’t my thing, but you get the picture. Constituencies that are forecasted to vote for one candidate by a big margin are at the middle of the snakes, while tighter races are at both ends.

Lib Dem marginals such as Brecon and Radnorshire aren’t included – that’s a whole other bag of snakes!

The Senedd 2021 snake

So what Plaid Cymru and the Conservatives need to do to put Labour under pressure at the Senedd is get them down from their current 29 seats to under around 27.

The first step to doing this is if their snakes chomp into Labour’s seat allocation. Plaid Cymru will be looking to chomp their way through seats like Llanelli, Cardiff West and Caerphilly.

The Conservatives have their eyes of the Vale of Glamorgan, Vale of Clwyd, Gower, Wrexham, Cardiff North, and Clwyd South.

Labour meanwhile aren’t in an entirely defensive position – they will be looking to gobble up some constituencies of their own including Rhondda from Plaid Cymru and also Carmarthen West and South Pembrokeshire and Preseli Pembrokeshire from the Conservatives.

It’s possible of course that parties will take seats where they need a bigger swing and fail to take a few where they need a smaller swing. For instance, Plaid Cymru currently look more likely to win Caerphilly than Blaenau Gwent or Cardiff West.

The Conservatives too had a lot of luck in the north of Wales in the 2019 General Election but much less in their target seats, like Gower, in the south.

Current polls have Plaid Cymru set to take Llanelli and the Conservatives to take seats such as the Vale of Glamorgan, Vale of Clwyd and Wrexham, putting Labour down four constituency seats.


It’s not quite that easy however as we also need to take into account the regional list. If Labour lose Llanelli to Plaid Cymru, say, they will likely get at least one more seat on the Mid and West Wales regional list in compensation.

If they drop a seat in the north of Wales they are, again, likely to get a seat in compensation on the list.

What may really matter therefore in Labour falling below that 27-26 seat margin where a minority Welsh Labour government is viable isn’t just how many seats they lose but where they lose them.

In the South Wales West, South Wales Central and South Wales East regions they completely dominate the constituencies already and so it’s almost impossible for them to win a regional list seat there.

It is here therefore that the Conservatives and Plaid Cymru can do the most damage if they start picking off constituency seats – the Vale of Glamorgan and Gower in the case of the Conservatives, and places like Neath and Caerphilly in the case of Plaid Cymru.

Another route forward to bringing down Labour’s seat numbers is if they sustain very heavy losses in the north of Wales, as they did in the 2019 General Election – and don’t get as many regional seats back in compensation as they’ve lost.

As a result, snakes chomping into one another is probably not the best way of visualising the outcome of Senedd elections. But it is useful in giving us some idea which seats are targets and which are safe.

And despite Conservatives and Plaid Cymru being ideological opposites, it will take a good night for both their Senedd snakes to squeeze the life out of Labour.

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Graham Burnby-Crouch
Graham Burnby-Crouch
3 years ago

Whatever the question the answer surely cannot be vote Conservative. This undermines the cause of independence and hurts the people of Wales.

Owain Morgan
Owain Morgan
3 years ago

A Labour/Plaid agreement or Coalition is the best outcome. It will keep the Tories out and secure stable Government. I also hope you we didn’t have any Anti Senedd Gravy train fools as MSs this time. The Kipper/Brex**it mess was bad enough, but this Abolish group seem even worse.

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