Andy Burnham won the Makerfield by-election on 18 June 2026, securing 55% of the vote and defeating Reform UK's Robert Kenyon by more than 20 percentage points. The result returns Burnham to the House of Commons and, under Labour Party rules, now makes him eligible to stand in any future leadership contest — a threshold he could not previously meet as he was not a sitting member of the Parliamentary Labour Party.
The by-election was triggered on 14 May 2026 when Josh Simons, the sitting MP for Makerfield, resigned his seat. Burnham not only retained the share of the vote Labour won in the constituency at the 2024 general election but increased it. Under the rules governing combined authority mayors, Burnham's election to the House of Commons immediately disqualified him from the Greater Manchester mayoralty. The statutory deputy mayor, Paul Dennett, takes over as acting mayor, and a mayoral by-election must be held by 6 August 2026.
In the weeks before the vote, sterling had slumped to a one-month low against the dollar, trading down 0.3% at $1.3363, as talk of a challenge to Starmer gathered momentum [Source: CNBC]. The yield on 10-year gilts was well above 5%, having risen more than one basis point to reach 5.137% [Source: CNBC]. Ahead of the result, CIBC estimated that a Burnham victory could push EUR/GBP (EURGBP=X) up by around 0.2%, while a surprise defeat could have triggered a 0.8% move in the opposite direction [Source: GB News]. UK government bonds were already trading at higher yields than many comparable G7 nations, with economists attributing part of that premium to political uncertainty and investor concerns over the future path of fiscal policy [Source: GB News].
Prior to the result, Ebury's head of market strategy Matthew Ryan labelled the market risk posed by a Burnham victory as 'very high' [Source: CNBC]. Prediction market Polymarket had ranked Burnham as the most likely next Prime Minister of the UK, assigning a 59% probability of him taking over in 2026 against a 25% likelihood of Starmer remaining in post for the remainder of the year [Source: CNBC]. Separately, in the lead-up to the vote, Burnham abruptly cancelled a call aimed at placating investors nervous about his potential policy mix, according to reporting by the Financial Times cited by CNBC.
The backdrop to Burnham's return to Westminster includes sustained internal pressure on Starmer, whose premiership has faced intense scrutiny following a crushing defeat for Labour in the UK's local elections. Dozens of lawmakers within Starmer's own party have called for his resignation; under Labour Party rules, a leadership vote would be put to party members if a challenger gains sufficient support from sitting politicians. An earlier attempt by Burnham to contest a by-election in January 2026 was blocked by Starmer loyalists. Burnham has previously argued that the UK should not be 'in hock' to bond markets and positioned himself as more of an interventionist, favouring stronger public control in areas such as transport and essential services funded in part through increased borrowing. Deutsche Bank analysts noted he subsequently partially rowed back some of those comments, pointing to a February statement in which he acknowledged that bond markets should not be ignored.
Sources: Sky News, BBC News, Bloomberg, House of Commons Library, Currencies Direct, CNBC, GB News.