Keir Starmer Resigns: Ex-PM Triggers By-Election Headache for Andy Burnham
Keir Starmer’s decision to resign as an MP has created an unexpected political challenge for Britain’s new Prime Minister, Andy Burnham. Just weeks after leaving Downing Street, Starmer has now decided to step away from Parliament altogether, triggering a by-election in his former constituency of Holborn and St Pancras. What might normally be regarded as a routine change in parliamentary representation has instead become an important early test of Burnham’s leadership and Labour’s ability to retain support in a politically changing Britain.
Starmer announced his decision on September 1, 2026, saying that after reflecting over the summer he had concluded that it was the right time to leave the House of Commons and hand responsibility to a successor. He had previously indicated that he intended to remain an MP until the next general election, which is not expected until 2029. His decision to leave Parliament earlier than planned has therefore been portrayed by some critics as another political U-turn.
For Andy Burnham, the timing could hardly be more challenging. Burnham became Prime Minister in July after Starmer’s resignation as Labour leader and Prime Minister. His first appearance as Prime Minister in the House of Commons took place on September 1, the same day Starmer’s departure from Parliament was announced. Burnham is therefore being forced to manage both the beginning of his own political programme and the electoral consequences of his predecessor’s decision.
The by-election will take place in Holborn and St Pancras, a constituency that has traditionally been one of Labour’s safest seats. Starmer represented the constituency from 2015 and maintained Labour’s hold on the seat through several difficult periods for the party. However, Labour’s majority has fallen considerably. At the most recent general election, Starmer won with a majority of around 11,000 votes, compared with approximately 27,000 in 2019.
This decline is important because the constituency is no longer politically insulated from wider national trends. The Green Party has made significant progress in Camden, and local election results have demonstrated that Labour faces a serious challenge from the Greens in parts of the constituency. At the local elections, the Greens increased their representation in Camden and became the official opposition to Labour through the Green and Progressive Alliance.
The by-election could therefore become much more competitive than the traditional reputation of Holborn and St Pancras might suggest.
For Burnham, this creates a difficult political calculation. A Labour victory would provide an early demonstration that the party remains capable of winning in London under his leadership. A significant increase in Labour’s majority could strengthen the argument that Burnham has successfully begun to rebuild the party’s popularity following the political difficulties of the Starmer era.
But a poor result could immediately raise questions about whether Labour’s recovery is genuine.
The Green Party is particularly important in this contest. Zack Polanski, the Green Party leader, is widely expected to be interested in standing, although internal discussions within the party have also focused on potential candidates with strong pro-Palestinian credentials. Former Labour and left-wing candidate Andrew Feinstein, who previously performed strongly against Starmer, has also been discussed as a potential contender.
This presents Labour with a potentially serious problem. In a constituency where the Greens have already established a substantial local presence, a strong Green campaign could turn the by-election into a referendum on Labour’s direction under Burnham.
The political environment is also different from the one that existed when Starmer first became Labour leader. The party won a large majority in the 2024 general election, but its political position subsequently weakened. The rise of Reform UK, strong Green performances in some areas and growing dissatisfaction with mainstream political parties have made British politics considerably more fragmented.
Burnham’s rise to the premiership was itself closely connected to this political transformation. His victory in the Makerfield by-election was interpreted as evidence that Labour could resist Reform UK in northern England. The result helped accelerate pressure on Starmer and ultimately contributed to his decision to resign as Prime Minister.
Burnham now faces the irony of having benefited politically from one by-election while immediately confronting the consequences of another.
The Holborn and St Pancras contest is particularly significant because it will test whether Burnham’s political appeal extends beyond his traditional base in Greater Manchester and northern England. Much of his political identity has been built around regional inequality, devolution and the argument that Britain needs to transfer power away from Westminster and London.
Yet London remains a crucial part of Labour’s electoral coalition. If Burnham wants to build a broad national movement, he must demonstrate that his political programme can attract voters in metropolitan London as well as in northern communities.
His first Commons speech as Prime Minister offered an indication of how he intends to achieve this. Burnham promised to reduce living costs, revitalise local communities and increase public control over essential services such as water, housing, energy and transport. He also criticised decades of centralisation and economic policies that he believes contributed to Britain’s low growth.
These policies could potentially appeal to voters in Holborn and St Pancras, particularly younger voters facing high housing costs and expensive living expenses. The constituency contains large numbers of renters, professionals, students and younger residents who may be receptive to Labour’s promises on housing and public services.
However, the Greens could argue that Burnham’s government does not go far enough on environmental policy, social justice or the situation in Gaza. In a constituency with a politically engaged and progressive electorate, such issues could play an important role.
The Labour campaign will therefore have to defend Burnham’s record while simultaneously explaining why voters should continue to support the party after the difficult final months of Starmer’s premiership.
Starmer’s personal political legacy will inevitably be part of the campaign. He led Labour to its historic 2024 general election victory, ending years of Conservative government and returning Labour to power with a large parliamentary majority. However, his government subsequently struggled with falling popularity, internal tensions and concerns about the party’s electoral prospects. He eventually resigned as Labour leader and Prime Minister in July 2026.
Starmer has now indicated that his future will focus more heavily on international affairs. He plans to continue work involving defence, security, trade and technology, as well as efforts to combat violence against women and girls. His departure from Parliament effectively closes a major chapter in his political career.
For Burnham, however, Starmer’s departure does not mean that the previous government disappears from public memory. Voters will inevitably judge the new prime minister against the political situation he inherited.
This creates an important strategic question: should Burnham attempt to distance himself from Starmer completely, or should he emphasise continuity where it benefits Labour?
So far, Burnham has clearly sought to establish his own political identity. In his first Commons address, he argued that Britain needed a significant change in economic direction and promised greater public involvement in essential services. He also emphasised regional empowerment and the need to restore confidence in communities that he believes have been neglected for decades.
The Holborn and St Pancras by-election will provide an immediate opportunity to test whether voters respond positively to that message.
There is also a broader constitutional and political significance to the contest. Parliamentary by-elections are often treated as mid-term opportunities for voters to express dissatisfaction with the government rather than simply to choose a local representative. The outcome can therefore be interpreted as an early opinion poll on a new administration.
If Labour wins comfortably, Burnham can claim that his leadership is beginning to stabilise the party. If Labour loses, the result could create an immediate narrative of crisis.
The Greens, meanwhile, have an opportunity to demonstrate that their growing support is not limited to local elections. A victory in a constituency once associated with the Labour leader himself would represent an extraordinary symbolic achievement.
Nevertheless, Labour retains important advantages. The party has a long history in the constituency, a substantial organisational structure and a strong national profile. Polling cited in recent reporting has also suggested that Labour’s position has improved since Burnham became Prime Minister.
The result is therefore far from predetermined.
Ultimately, Keir Starmer’s decision to resign as an MP has created a test that Andy Burnham probably did not want so early in his premiership. The new Prime Minister is attempting to establish his economic and political agenda while simultaneously defending a Labour seat that is no longer as secure as it once appeared.
The by-election will be about more than replacing one former prime minister. It will be a test of whether Labour can rebuild its electoral coalition, whether Burnham’s political message resonates beyond his northern base and whether the Greens can transform growing local support into parliamentary representation.
For Starmer, leaving Parliament represents the final stage of a rapid political transition from prime minister to former politician focused on international affairs. For Burnham, however, his predecessor’s departure creates another demanding challenge at the very beginning of his premiership.
The stakes are therefore unusually high. A Labour victory would give Burnham valuable political breathing space and reinforce the impression that his leadership has begun to restore the party’s fortunes. A weak result or defeat, by contrast, could undermine the government’s authority before its major domestic reforms have even had time to take effect.
The Holborn and St Pancras by-election may consequently become one of the first major tests of the Burnham era. What begins as the resignation of one former prime minister could quickly become a referendum on the political future of his successor.