When Andy Burnham chose James Purnell as his future chief of staff, the decision not only reunited two old friends but also highlighted one of the most powerful and least understood jobs in British politics. The chief of staff role has no official job description and was invented on the fly, yet it has been central to the success of the only two Downing Street tenures this century that lasted a full parliamentary term: Tony Blair and David Cameron.
A chief of staff is the prime minister's most senior political adviser, responsible for enforcing the PM's priorities across government and speaking authoritatively for them in moments of internal conflict, crisis and deadlock. As Gavin Barwell, who held the role under Theresa May from 2017 to 2019, wrote in his memoir: "Whatever other roles the chief of staff to the prime minister may have, their primary responsibility is to keep their boss in office." Barwell also stressed the importance of being able to "tell truth to power" — few people are willing to say no to the prime minister or deliver unwelcome news.
“An explainer on the UK chief of staff role, using Purnell's appointment as a hook.”
Keir Starmer's time in office showed how difficult the role can be. He began by appointing veteran Whitehall trouble-shooter Sue Gray, then sacked her after a few months because he felt she lacked sharp political instincts. He replaced her with political strategist Morgan McSweeney, who eventually resigned over advice he had given on the choice of British ambassador to the United States. Critics said McSweeney spent too much time on electoral strategy and media management and not enough on running an effective government. In his final months, Starmer asked two aides — Jill Cuthbertson and Vidhya Alakeson — to hold the role on an interim, joint basis.
James Purnell, who was chief executive of Flint Global before being appointed by Burnham, brings a different background. He and Burnham have been friends and football teammates for about 30 years, and both served in Gordon Brown's cabinet. Purnell also held senior management positions outside politics. He has given up his shares in Flint, will have no ongoing financial interest in the company, and no access to Flint emails or systems. A Burnham team spokesperson said any future conflicts of interest would be "appropriately managed."
For UK readers, the chief of staff role matters because it shapes how effectively a government delivers on its promises and handles crises. A strong chief of staff can prevent policy drift, manage internal rivalries, and ensure the prime minister's agenda stays on track — all of which directly affect public services, the economy, and everyday life.
Q: What exactly does a UK chief of staff do? The chief of staff is the prime minister's most senior political adviser. Their primary responsibility is to keep the PM in office by enforcing priorities across government, managing the political team in Number 10, and speaking for the PM during internal conflicts or deadlocks. They must also be willing to tell the PM things they don't want to hear.
Q: How is the chief of staff different from other Number 10 aides? Unlike a policy adviser or communications director, the chief of staff oversees the entire political operation. They manage other political advisers across government and act as the ultimate gatekeeper to the prime minister. The role is not defined by law and has evolved differently under each PM.
Q: Why has the role been controversial under recent prime ministers? Keir Starmer struggled to find a stable chief of staff. His first appointee, Sue Gray, was seen as lacking political instincts; his second, Morgan McSweeney, resigned after controversy over his advice on a diplomatic appointment. Critics said McSweeney focused too much on electoral strategy. The role requires a blend of political judgment and administrative skill that is hard to find.
What happens next: If Andy Burnham becomes prime minister, James Purnell will take on the chief of staff role. The appointment has caused unease among some on the Labour left because of Purnell's tenure at Flint Global, a lobbying firm that advised BP, Amazon, Apple and Uber. Purnell has severed his ties with the firm, but questions about potential conflicts of interest may persist. The effectiveness of his partnership with Burnham — on and off the pitch — will be tested in the pressures of government.