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Play Fantasy Senedd 2021!

Exactly one year before the Senedd Election in 2021, Deryn, Wales’ leading public affairs agency, has launched a new online Seat Projector which can be used to show which seats may change hands at one of the most interesting elections since devolution began.

Using the 2016 election results as the baseline, the online tool shows which seats may change hands given a predicted swing applied uniformly across Wales. Entering the latest opinion polling data demonstrates visually which constituencies and regional seats would change hands, or you can enter your fantasy outcome to see what sort of national swing your party would need to win a majority.

Entering the latest Welsh Political Barometer Survey results provided by YouGov for ITV Wales projects that 9 constituency seats and 11 regional seats could change hands if a uniform swing was applied across Wales, with Labour losing 6 seats, and the Conservatives winning an extra 15 seats to become the largest party at the Senedd.

Cathy Owens, Director of Deryn, said:

“We developed a similar tool ahead of the last General Election, and the political geeks of Wales loved it. This one is a bit more complicated, as we had to incorporate both the constituency and regional polling, and one affects the other, so the maths is really complicated! We worked with our digital agency Blue Stag on the methodology, which uses the d’Hondt system to allocate top up regional seats.

We’re so pleased with it, and I know that the geeks are going to love it. We’re also going to work on some further school materials, because 16 and 17 year olds in Wales are going to be voting in this election for the first time, and it’s going to be an accessible tool to engage young people on their mobiles, showing them how their first vote could change the make-up of the Senedd.

We’re hosting a webinar with Roger Awan-Scully to launch the Seat Projector at 7pm on 6th May so that anyone can have a go and also hear Roger’s view on the latest polling.”

Kirsty Bowen, Leader Developer at Blue Stag, said:

“We built the parliament seat projector last year with Deryn and it was great to have the opportunity to collaborate again to extend this into the Senedd Seat Projector. We always like a technical challenge, and this was certainly one. We hope that people will enjoy using the tool which will allow them to see a visual representation of the country’s political outlook.




The Deryn Seat Projector is at

For more information contact Cathy Owens on or visit



For a bird's eye view.
Am olwg oddi uchod.

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