Reform UK has reached a constitutional milestone that would have seemed implausible just months ago: the insurgent party now has more defected Conservative MPs than members elected under its own banner, fundamentally altering the dynamics of right-wing politics in Britain.
Following defections by Suella Braverman, Robert Jenrick, Danny Kruger, and Andrew Rosindell, five of Reform's eight sitting MPs are former Conservatives. Only Richard Tice, Nigel Farage, and James McMurdock were originally elected wearing the Reform rosette, whilst Lee Anderson—who defected before the 2024 election—technically counts as a Reform recruit rather than a newly-elected MP.
As they say in Westminster, 'the constitution is what happens'—precedent matters more than law. This pattern of defection recalls the birth of the SDP in 1981, when the 'Gang of Four' peeled away from Labour, though those figures created a new party rather than joining an existing one. What we're witnessing now is arguably more significant: the wholesale absorption of a major party's right wing by an outside force.
The implications for Parliamentary procedure prove immediately awkward. Reform technically remains the fifth-largest party by overall seat count, but its composition raises questions about legitimacy that no amount of polling success can easily answer. These MPs were elected as Conservatives, many in seats where Reform candidates ran against them. Their constituents voted for Conservative manifestos, Conservative whipping arrangements, and Conservative government.
The defections also reveal the hollowing out of Conservative Party discipline under successive leaders. Boris Johnson's expulsion of Brexit rebels in 2019 established a precedent for ideological purges, but he at least commanded electoral success. The current leadership offers neither ideological coherence nor polling strength, leaving ambitious backbenchers eyeing the exits.
What makes this exodus particularly striking is its acceleration. The first defection—Anderson's—occurred in March 2024. The latest batch suggests a gathering momentum that could trigger further departures, particularly if Reform continues to lead in opinion polls. Several Conservative MPs face difficult re-election battles in constituencies where Reform runs strong.
The Constitutional implications extend beyond party politics. Britain's system depends on MPs representing constituents who elected them under specific party labels. Mass defections strain this principle, yet no mechanism exists to trigger by-elections except in cases of criminal conviction or bankruptcy. The recall petition system requires an MP to be suspended from Parliament for at least 10 sitting days—a threshold defection does not meet.
Opposition parties face their own dilemma. Labour benefits from Conservative chaos, but Reform's rise on the right potentially splits the anti-Labour vote in ways that could entrench the current government for years. The Liberal Democrats, traditionally beneficiaries of Conservative weakness in southern seats, now find themselves competing with Reform in post-industrial areas they once considered winnable.
The broader pattern suggests British politics is experiencing a fundamental realignment similar to those that transformed European party systems in the 2010s. The Conservative Party, which has governed Britain for 14 of the past 18 years, faces an existential question: does it chase Reform rightward, or does it seek to rebuild its traditional centrist coalition? The answer will determine whether it survives as a major political force.
