Social Democratic Party
Small British party led by William Clouston, standing in the 13 August Clacton by-election.
The SDP gained two councillors elected for Reform UK in August 2026: Rhys Carr in Wakefield on 6 August and Jack McGlenen on Durham County Council, recorded on 20 August. Its leader William Clouston had stood in the Clacton by-election.
Last refreshed: 7 October 2026 · Appears in 2 active topics
Can the SDP make a mark in the crowded Clacton by-election?
Timeline for Social Democratic Party
Mentioned in: Labour takes Hirst and Amble from Reform
UK Local Elections 2026Mentioned in: Reform down to 50 of 98 Durham seats
UK Local Elections 2026Mentioned in: Three more of Reform's May intake quit
UK Local Elections 2026Mentioned in: Durham councillor joins UK Social Democratic Party
UK Local Elections 2026Gained its first Wakefield member
UK Local Elections 2026: Carr takes his Reform seat to the SDPBackground
The Social Democratic Party (SDP) is a small British party led by William Clouston. It is distinct from the Social Democratic Party that Labour defectors founded in 1981, which merged into the Liberal Democrats in 1988, and unrelated to Germany's SPD.
It describes itself as economically interventionist and communitarian, and it opposes mass immigration. That combination does not match Reform UK's economically liberal populism. The party typically stands in only a few seats nationally; Clouston contested the Clacton by-election on 13 August 2026.
In 2026 it gained council seats through defections rather than elections. Rhys Carr joined on 6 August after leaving Reform UK, and Jack McGlenen, originally elected for Reform on Durham County Council, was recorded as joining on 20 August.
Reform defectors give the SDP seats
Rhys Carr won Wakefield's Ackworth, North Elmsall and Upton ward for Reform UK in May 2026, left the party in June and joined the SDP on 6 August. He became the party's first member of Wakefield council, and keeps the seat because the mandate belongs to him rather than the party label.
A second followed in the North East. Jack McGlenen, a Durham County Council member for Dalton and Dawdon originally elected for Reform UK in 2025, moved from Independent to the SDP. Open Council Data recorded the switch on 20 August, a record-update date rather than a confirmed announcement.
The SDP enters Clacton
When nominations closed on 17 July for the 13 August Clacton by-election, SDP leader William Clouston was one of a record 34 candidates, alongside Nigel Farage and Laurence Fox.
None of Labour, the Conservatives, the Lib Dems, The Greens or Restore Britain put up a candidate, which left Clouston on a ballot without the main parties and gave the SDP a rare national platform. The party usually fields candidates in only a handful of seats, so national coverage of it is uncommon.
The SDP gets a rare platform
What does the Social Democratic Party stand for?
Is the Social Democratic Party the same as the 1980s SDP?
Who leads the Social Democratic Party?
Written with AI from Lowdown's published reporting. Not individually reviewed by an editor. Updated 7 October 2026. Editorial standards.