Will this crucial Budget be designed by PM or No 11?

Keir Starmer’s mini-reshuffle of 10 Downing Street was widely interpreted as an assertion of prime ministerial power over Rachel Reeves, the chancellor. The key part of the jigsaw was the appointment of Darren Jones, previously Reeves’s deputy as chief secretary to the Treasury, to the new post of “chief secretary to the prime minister”, based in No 10.

- JOHN RENTOUL

At the same time, Starmer brought in Dan York-Smith, a Treasury official, to be his closest civil servant, principal private secretary, and appointed an economic adviser, Minouche Shafik, a former deputy governor of the Bank of England - not having had one until now.

Does this mean that the prime minister is beefing up his team in order to put his mark on the forthcoming Budget - in which the government is under intense pressure to break its manifesto promises by raising one of the main taxes and to cut public spending?

Who decides the Budget measures?

Conventionally, the main Budget decisions are taken jointly by the prime minister - who retains the historical title of first lord of the Treasury - and the chancellor. But in practice, the balance of power between Nos 10 and 11 can tilt one way or the other.

Tony Blair was once reduced, only half-jokingly, to pleading with Gordon Brown to “give us a clue” as to what might be in a Budget that was only a few days away.

David Cameron and George Osborne had a more harmonious relationship, although it was complicated most of the time by the need to consult the Liberal Democrats.