Reform UK, ‘The Biggest Party in Great Britain’

Reform UK has moved from the margins to the centre of UK politics, with recent polling and election results showing the party competing at the highest level. This rise across the United Kingdom places Reform UK as the biggest party across Great Britain, ahead of Labour and the Conservatives.

Together, the Welsh and UK-wide data point to a significant realignment, particularly in areas that have traditionally been Labour strongholds.

Recent Wales-focused opinion polls conducted during 2025 indicate that Reform UK is now one of the strongest parties in the country.

In a YouGov / ITV Wales (Barn Cymru) poll on Senedd voting intention:

• Plaid Cymru: ~30%

• Reform UK: ~29%

• Labour: ~14%

• Conservatives: ~11%

• Liberal Democrats and Greens: each in the mid-single digits

This places Reform effectively level with Plaid Cymru and well ahead of Labour, a notable shift in a political system long dominated by Welsh Labour.

The same polling series, when asking about Westminster voting intention in Wales, showed Reform UK narrowly in the lead:

• Reform UK: ~29%

• Plaid Cymru: ~23%

• Labour: ~18%

• Conservatives: ~13%

Other Wales-wide polls across 2025 have reported Reform’s support consistently in the mid-to-high 20s, sometimes reaching around 30%, reinforcing the picture of a party firmly established in the top tier.

Polling trends have been backed by electoral performance. In the Caerphilly Senedd by-election, Reform UK finished second with around a third of the vote, ahead of Labour, which fell to just over ten per cent. Although Plaid Cymru won the seat, the result underlined Reform’s ability to mobilise substantial support in South Wales.

At local level, Reform UK has also won council seats in Welsh by-elections, including victories in areas previously regarded as safe for Labour. These results suggest that Reform’s polling support is translating into real votes rather than remaining abstract.

National Polling: Reform as a Leading UK Party

Reform UK’s Welsh rise mirrors its national standing. Across Britain, several major polling companies have published surveys in which Reform ranks first or joint-first in UK-wide voting intention.

Recent national polls during late 2025 have shown figures in the following range:

• Reform UK: approximately 27–33%

• Labour: approximately 18–21%

• Conservatives: approximately 16–19%

In some individual polls, Reform has led Labour by 8–10 points, marking the first time in modern UK politics that a newer party has consistently challenged both major parties at this scale.

This national position strengthens Reform’s profile in Wales, where voters appear increasingly influenced by UK-wide dissatisfaction with traditional parties.

What the Numbers Mean for Wales

Under the Senedd’s proportional electoral system, polling at or near 30% would likely translate into a substantial number of seats for Reform UK, even if it does not finish first. Analysts have suggested that, on current figures, Reform could emerge as either the largest or second-largest group in the Senedd after the next election.

For Welsh Labour, regularly polling in the low-to-mid teens, the data points to its weakest position in Wales for a generation. Plaid Cymru remains strong, but Reform’s rise introduces a new competitive dynamic that could reshape governance in Cardiff Bay.

Polling data from Wales and across the UK shows Reform UK consolidating its status as a leading political force. In Wales, the party is polling at levels that place it alongside, and sometimes ahead of, long-established rivals, while nationally it has topped or led several voting intention surveys.

As the next Senedd election approaches, Reform UK’s gains in Wales cannot be separated from its broader national momentum. Together, they suggest a profound shift in the political balance, with Reform now firmly embedded as a central player in both Welsh and UK politics.

Pic . House of Commons