May 2026 has delivered the most significant reshaping of devolved politics in a generation.
Elections to both the Scottish Parliament and the Senedd Cymru have produced new political classes that bear little resemblance to what came before; and the scale of the change is without modern precedent.
These are among the key findings of Polimapper’s newly published Class of ’26 white papers (one for Holyrood, one for the Senedd), which examine in depth what has changed, and who the new political class actually is.
At Holyrood, 64 of the 129 MSPs (49.6%) are newly elected, the highest intake since the Scottish Parliament was established in 1999. At the Senedd, 67 of 96 Members (70%) are new to Cardiff Bay, a figure that surpasses anything ever recorded in postwar British politics.
To put the combined scale of change in context: since the 2024 general election brought 350 new arrivals to Westminster (albeit 15 of them had sat in previous parliaments), a further 131 new legislators have now arrived across Holyrood and the Senedd.
In just two years, 481 of the 875 politicians representing the people of Great Britain, 55% of the total, have changed.
Even setting aside the 36 new positions created by the Senedd’s expansion in size, the genuine turnover across the three chambers still stands at 445 legislators, or 51% of the combined total.
For public affairs professionals operating across Westminster, Holyrood and Cardiff Bay, the world looks very different to the one they knew in May 2024.
Scotland: A parliament transformed
The SNP retains its position as the largest party at Holyrood with 58 MSPs (45%), but its share of the chamber is at its lowest since before the 2011 landslide.
The more dramatic stories lie elsewhere. The Scottish Conservatives, with just 12 MSPs, have reached their lowest ever level of representation. Labour holds 17 seats, a further decline from an already diminished position. Meanwhile, Reform UK has arrived at Holyrood for the first time with 17 MSPs, while the Scottish Greens have grown to 15 – nearly double their previous best.
The scale of change was driven by a record 42 retirements and a significant reshaping of the electoral map that saw a quarter of those who stood for re-election defeated. Only two MSPs, Jackie Baillie and John Swinney, have sat continuously at Holyrood since 1999.
Number of new MSPs by election year
Wales: The most dramatic result in devolved history
If Holyrood’s transformation was striking, the Senedd’s was seismic. Plaid Cymru has surged to 43 seats, 45% of the chamber and its highest share since devolution began.
Labour, which had held between 43% and 50% of seats in every previous Welsh election, has been reduced to just nine seats. Reform UK, contesting the Senedd for the first time, has taken 34 seats. Close to four in ten of the chamber’s members represent parties that had never won a Senedd seat before.
Three factors combined to produce this result: the expansion of the Senedd from 60 to 96 members, a record retirement rate among Labour MSs, and the defeat of 16 incumbents who stood for re-election. As at Holyrood, just two Members, Lynne Neagle and Elin Jones, have sat continuously since 1999.
Rate of new MSs by election year
Shared characteristics of the Class of ’26
Across both chambers, several common threads emerge. Both parliaments are younger than their predecessors, with around a quarter of members now aged under 40 in each institution.
Both replicate the localism trend that Polimapper first identified in its Class of ’24 study ahead of the 2024 general election: 56% of Holyrood’s constituency MSPs went to school within the seat they now represent, and 54% of Senedd members did likewise. Rightly or wrongly, local roots have become as important as party allegiance in determining who gets selected.
Reform UK’s arrival is another shared feature. In both parliaments, 94% of Reform’s elected members are new. Many come with prior Conservative backgrounds: 29% of Reform MSPs at Holyrood previously stood for or represented the Conservatives, rising to 38% among Reform’s Senedd group.
Number of MSs by party
What this means for public affairs professionals
The combined effect of these elections is that the political map across Scotland and Wales has been redrawn almost entirely. In practical terms, this means that relationships built over years with former members need to be rebuilt from scratch – and quickly.
That is precisely the challenge Polimapper’s Class of ’26 reports are designed to help with.
Each white paper goes beyond the headline numbers to give public affairs and advocacy professionals the insight they need to engage effectively with the new intake.
The reports cover the demographic profile of new and returning members, their career backgrounds (from health and law to farming and the armed forces), their prior political experience, and the extent of their local ties to the communities they now represent.
For anyone seeking to understand not just who the new members are, but what has shaped their outlook and where their interests are likely to lie, the reports provide a level of detail that goes well beyond anything available elsewhere.
Both the Holyrood and Senedd Class of ’26 reports are available to download now. Click the images below to download your copy.
