Keir Starmer steps down as UK Prime Minister

Keir Starmer formally announced his intention to step down as UK Prime Minister, with Labour set to choose a new leader before Parliament returns in September. Andy Burnham remains the overwhelming favourite to succeed him, with prediction markets currently assigning him approximately a 96% probability of becoming the next Labour leader. A notable reflection of the current political era is that King Charles, who has been on the throne for less than four years, is already on his third prime minister and could soon welcome a fourth. By comparison Queen Elizabeth II saw 15 Prime Ministers from Churchill to Truss over her 70-year reign. 

The route to Number 10 remains uncertain. One scenario is a relatively swift transition, with Burnham securing sufficient support from MPs and senior Labour figures to become leader unopposed. Another is a full leadership contest involving alternative candidates, extending the process through the summer.

For investors, however, the focus is increasingly shifting away from personalities and towards policy. While Burnham is seen as being from Labour’s more interventionist wing, markets have so far taken comfort from indications that fiscal discipline would broadly remain intact. Much will depend on the economic team that emerges, particularly the choice of Chancellor and whether existing fiscal rules remain in place.

Perhaps the most notable aspect of today’s developments is how little markets have reacted. The FTSE 100 equity index, at the time of writing, is up marginally, outperforming other equity markets in the region.

Sterling is only slightly weaker today and remains close to its weakest level of the year against the US dollar. However, much of that reflects broader dollar strength following a more hawkish tone from the US Federal Reserve (Fed). 

Similarly, UK gilt yields are around 10 basis points higher than a week ago, although most of that move reflects the global repricing in bond markets following the Fed meeting. Unlike the market reaction seen during the 2022 mini-budget episode, there has been little sign of stress in UK government bonds.

One interpretation is that much of the political uncertainty has already been priced in as Labour’s popularity weakened and Reform gained support over recent months. For now, investors appear to be treating this as a leadership transition rather than a challenge to UK fiscal credibility.

Although Burnham has focused primarily on broader economic and political themes rather than detailed policy proposals, there are several areas wealthy individuals and families may wish to monitor closely.

Burnham has reaffirmed Labour’s commitment not to increase the main rates of income tax, VAT or National Insurance, although he has indicated a willingness to revisit the employer National Insurance increases introduced in 2024. He has also been a long-standing supporter of reforming property taxation, including council tax and stamp duty.

At this stage, these remain broad policy positions rather than fully developed proposals. They highlight why investors are paying close attention not only to who becomes Prime Minister, but also to the Chancellor, Treasury team and the fiscal programme that emerges from any new administration.

Bottom line: Markets currently appear to view a potential Starmer-to-Burnham transition as a political event rather than a fiscal one. Burnham may, however, face a different challenge to the one Starmer faced in 2024. Starmer’s landslide victory reflected, in many respects, a vote for change after years of Conservative rule. Burnham is likely to need a more clearly defined economic agenda and policy platform as voters become increasingly willing to switch allegiances between Labour, Reform and the Conservatives. For investors, the key question remains whether that agenda is accompanied by fiscal discipline and credible economic leadership.

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