Labour leadership uncertainty highlights growing ignorance about the UK’s constitution

Uncertainty about the prime minister’s future has seen an outbreak of constitutional speculation. Back in February, when discussion about replacing Keir Starmer as Labour leader notched up a level, some briefings to the media suggested an interim prime minister could be appointed while a leadership contest was run. Then, last week, apparently as part of No10 briefings to the media on why replacing Starmer was a bad idea, the argument was made that government would be effectively shut down because of constitutional restrictions throughout a contest.  

Both examples highlight misunderstandings about core constitutional principles.  

The distinction between the roles of party leader and prime minister must be understood

Every recent challenge to a prime minister has triggered debate about how prime ministers are chosen and what mandate they have, often conflating the role of party leader and PM. The two roles are closely related, but distinct. A party leader who commands confidence in the House of Commons (which does not mean they must hold a majority) can become prime minster. If the governing party wants to change the leader, the prime minister still holds that role ‘unless and until’ they resign. By extension, they must resign as prime minister once a new leader has been elected, since that demonstrates that they can no longer command confidence.

However, the Labour party rulebook’s section on replacing the party leader sits slightly uncomfortably with the UK constitution’s approach to replacing a prime minister. The rulebook states that if the leader becomes ‘permanently unavailable’ when the party is in government the cabinet ‘shall, in consultation with the NEC, appoint one of its members to serve as party leader’ until a leadership election is concluded. This is, in some ways, a helpful inclusion – if the distinction between the two roles of party leader and PM is understood.  

Constitutionally, the UK cannot be without a prime minister. If a PM was suddenly ‘permanently unavailable’ – whether they had resigned as prime minister with immediate effect or had died in office – then the constitution expects the cabinet, as the Monarch’s senior advisers, to recommend who should take the role. The Labour rulebook therefore works to ensure that there is a prime minister in place, but also that they have the necessary legitimacy as interim leader, until a new leader is elected.

If Starmer chose to resign both roles at once, then the Labour rulebook approach would help. But the reason why all recent mid-term departing prime ministers have remained in post during changes of leader (including Tony Blair when Gordon Brown was in the process of being elected as Labour leader), is because the UK constitution has no concept of an acting prime minister. You are either prime minister or not. A holder might conceive that they are temporarily in the role, but the constitution imparts on them all the rights and responsibilities that the office brings. This also means that the rulebook’s clause stating that acting leader ‘may fill any vacancies that arise in the cabinet, shadow cabinet, or other frontbench positions, but shall not otherwise alter their composition’ does not apply to the prime minister. Prime ministers’ power derives from their ability to recommend who serves in government. It is quite the awkward inconsistency.  

Formal pre-election restrictions don’t apply during a party leadership contest

The same continuity of government principle applies to whether formal election restrictions on government exist during a party leadership contest. They do not. The government continues in office, but a cabinet may sensibly choose to restrict some government activity during a contest, particularly if the sitting PM has been shown to have lost the confidence of his MPs.  

During general elections the restrictions are in place to ensure the civil service’s impartiality is protected, to ensure government resources are not unfairly weighted against other political parties, and because Parliament has ceased to exist while MPs are being elected. During an internal party contest, civil servants cannot be used in campaign activity, speeches, social media or so forth, but this also applies in normal times. Any actions conducted as the government would have to be clearly delineated. Managing that line could prove awkward, it might require heavy-handing policing from officials, but the line is there.  

While there are no formal restrictions on government activity, governments have chosen to limit their activity when facing a change of leader. However, it is trickier to set down definitive rules since the manner of a leader’s departure matters. Labour rules mean that if the incumbent leader was challenged but chose to stand in a contest, then a lack of confidence wouldn’t be demonstrated until the results were known. Conservative party rules include a party confidence vote in the leader, but recent prime ministers have stood down after political pressure.  

In 2022, Boris Johnson’s government decided that no new government policy would be announced until a new leader was chosen – the manner of Johnson’s resignation an acknowledgement of confidence lost. Starmer could yet find himself in the same position, but this is still a grey area. Starmer could announce he was stepping down, and constitutionally it could be argued his government is still viable: as Theresa May showed, prime ministers can still conduct significant policy making in the post-resignation announcement period, if their cabinet supports them. If, in the scenario of Starmer setting a departure timetable, the government chose to put in place some restrictions, then this still does not mean government would be constitutionally in stasis. Even the full general election rules don’t prevent governments taking major decisions in the national interest.

Constitutional comprehension cannot be assumed – it must be cultivated

Our politics is particularly fractious and volatile. Public, and market, confidence in government matters. So ensuring that the right messages are being conveyed to the public is crucial to avoid constitutional confusion or controversy. If the public believe a PM must resign instantly, then prime ministers are at risk of being accused of ‘squatting’ in No10, as happened to Gordon Brown in 2010. If Starmer does decide to step down in the coming weeks, or months, he and his ministers will not want the public or the media thinking the government can take no meaningful decisions, particularly if crisis hits.  

The UK does not have a codified constitution; but it does have plenty of documents (and officials) to help guide understanding of constitutionally complex situations. There is even a Cabinet Manual, though it has not been updated since 2011.  

People may not agree with how the constitution currently works, and there are many parts of it that need proper examination. However, as volatility grips British politics once again, politicians should resist creating more uncertainty for the public through misrepresenting – or deliberately misunderstanding – a set of principles and rules which might not suit their immediate political agenda or personal goals.