The bond market will burn Andy Burnham

Bond markets have a habit of reminding governments that they, not politicians, determine the price at which the state can borrow. Despite Andy Burnham’s message to the New Statesman last September that we’ve got to “get beyond this thing of being in hock to the bond market”, ten-year gilt yields remain around levels not seen since the aftermath of the Truss-Kwarteng mini-Budget.

There is no doubt that Andy Burnham’s affable persona and savvy TikTok game are a refreshing contrast to his predecessor’s stiffness. But while politicians trade in popularity, investors are interested in profits.

The rising stock of a prime minister is not necessarily reflected in the stock market. Indeed, external shocks have undone the plans of every occupant of Downing Street over the past decade. And each, whether Conservative or Labour, has reached for much the same economic playbook: more borrowing, higher spending, a larger state and, ultimately, higher taxes. With public debt already elevated and fiscal room increasingly scarce, Burnham may become the first prime minister forced to discover whether that playbook has finally reached its limits.

The public-sector finances data for June were marginally stronger than expected, with borrowing £300 million below the Office for Budget Responsibility’s (OBR) forecast. The cost of inflation-linked debt interest fell as the ceasefire in the Iran conflict pushed down energy prices. It was a timely reminder that governments do not control the most important variables in their own fiscal forecasts. With hostilities resuming, inflation is unlikely to remain so well-behaved, leaving Burnham’s fiscal headroom squeezed.

As one official reportedly told the new prime minister on arriving in Downing Street: you might not be interested in foreign policy, but it’s interested in you. Events overseas can force an indebted government into making unpopular decisions. The National Institute of Economic and Social Research (NIESR) estimates that higher energy prices and weaker growth have eroded most of the government’s fiscal headroom of £24 billion.

Higher inflation creates a double squeeze for the Treasury, raising debt-interest costs while reducing what departmental budgets can deliver. The director of the NIESR, David Aikman, says that “Commitments must be funded through taxation or savings elsewhere – not through more borrowing. That is the minimum needed just to hold the debt level where it is”.

Burnham vs the bond market

Burnham might want to get beyond bond markets, but unless he can unwind the relentlessly vicious circle of higher debt, higher deficits and stagnant growth, he will be doomed to repeat it. In her first act as chancellor, Rachel Reeves tried to pay for higher public-sector pay by removing the winter fuel allowance, sowing the seeds of her own demise. Taxing jobs through higher national insurance while raising the minimum wage made employment more costly, bearing down on growth. She then assembled a smorgasbord of wealth taxes owing to Labour’s manifesto commitment not to raise the three main taxes. Although Reeves reduced gilt issuance, it remains historically high. The Debt Management Office plans to issue around 50% more gilts this year than in 2022-2023. Burnham inherits the same fiscal constraints, but with Labour polling around ten points below the level that delivered its 2024 landslide, reducing his political as well as economic room for manoeuvre.

There is a more fundamental problem if he attempts revolutionary change. He was not even part of Labour’s 2024 election victory and, like all unelected prime ministers before him, will face complaints that he lacks a mandate to make difficult decisions. He has repeatedly stressed that Britain is a parliamentary democracy where parties choose their leaders. It is not unusual: 12 of the 19 people to serve as prime minister since 1945 first entered Downing Street between general elections. But that has never made governing easy. Only four went on to win a majority at the subsequent election.

With a fragmented electorate split at least four ways, Burnham may need little more than 25% plus one vote for a majority. Yet volatile voters are unpredictable. His strategy will be to unite the left by invoking his favourite bogeyman, the “Thatcher tribute act” Nigel Farage. Failing that, his programme itself has a distinctly left-wing flavour: capping household bills, re-industrialisation, stronger public control of utilities and a National Care Service. Politically, it is an attempt to rebuild Labour’s coalition. Economically, however, it assumes global events remain reasonably benign.

But the more he talks left, the more the bond markets will push him to the right. His priorities are expensive, and his options for paying for them are shrinking. The Laffer Curve is already alive and well in the disappointing revenues generated by a tax burden that has reached its highest level in decades.

Gilt issuance remains elevated, inflation an ever-present threat and he cannot afford to lose credibility by breaching the fiscal rules. “Events, dear boy, events,” as Harold Macmillan put it, still have a habit of overwhelming even the best-laid plans. Burnham’s greatest opponents may not reside in the House of Commons, but in the bond market.

This article was first published in MoneyWeek’s magazine. Enjoy exclusive early access to news, opinion and analysis from our team of financial experts with a MoneyWeek subscription.