Keir Starmer has attempted to wrest back control of economic policy from the Treasury by bolstering his No 10 team, bringing in the chancellor’s deputy and a former Bank of England chief to senior roles.

Before what is likely to be a tumultuous autumn for the government, he created two new roles with Darren Jones put in charge of day-to-day delivery and Minouche Shafik appointed the prime minister’s chief economic adviser.

Downing Street sources said the changes showed Starmer recognised his operation needed more economic heft to challenge Treasury thinking and avoid damaging pitfalls such as those over winter fuel payments and welfare cuts.

As MPs returned to Westminster after a difficult summer, during which Reform UK dominated the news agenda and soared ahead in the polls, Starmer wants to get on the front foot on issues including the economy and migration.

His internal No 10 reshuffle, which also covered the communications team and the policy unit, comes alongside a new economic pledge to deliver growth that “people can feel in their pockets”, a nod to the millions who are still struggling with the cost of living.

The extent of the shake-up reflects the sense that Starmer’s No 10 has increasingly struggled to impose its own narrative, and is instead mainly being shaken by external crises, notably the focus over the summer on migration, and Reform UK’s planned response to it.

Things are unlikely to improve in the short term, with the return of parliament presenting the prime minister and his team with a series of tough challenges, including the likely need for tax rises in this autumn’s budget.

Starmer rejected the idea the changes were prompted by crisis, arguing it was more a case of a new phase of government. “This should be seen more as moving on to the second phase than a reshuffle, because some of the positions are actually new positions,” he told the BBC.

Downing Street insiders acknowledged the changes were designed to give Starmer greater control over Whitehall, including of the Treasury, with No 10 evolving into a “command and control” operation.

“There have been things we should have seen coming where the chain of command and oversight were not what we wanted. This is Keir saying he wants to have a direct line of sight to everything. Darren knows the departments inside out because of the spending review,” one said.

“Keir has been thinking about how to fix things for the last couple of months and these are his appointments and this is his structure. There are decisions that were made in the Treasury – winter fuel being one of them – where No 10 did not take enough oversight.”

Another senior No 10 source said: “These are not people who have been appointed to be at odds with the Treasury or alternative power bases but to work with it. The economic agenda has to be aligned. But of course the PM needs to be able to shape it. Downing Street has to be able to challenge.”

A senior government insider denied the changes risked undermining Reeves’s position, saying she had been involved in discussions on them since earlier in the summer. “That is an analysis based on prime ministers and chancellors of the past – Blair and Brown, May and Hammond – when in fact these appointments make the Treasury’s job easier,” they said.

Jones, whose new title will be chief secretary to the prime minster, will be replaced as Rachel Reeves’s deputy by James Murray, who has been promoted from exchequer secretary. In turn, his role will be taken by Dan Tomlinson, the government’s “growth mission champion”, as Starmer seeks to reward the new 2024 intake.

However, there is not expected to be a wider reshuffle of the junior ministerial ranks this week, senior sources said, and cabinet ministers will stay in their current roles.

The communications operation will also be shaken up with Tim Allan, an adviser to Tony Blair in No 10 who went on to fund the PR firm Portland, coming in as executive director of government communications.

His appointment has caused some alarm in government, as he did some work for Russian president Vladimir Putin in the early noughties to reshape his own image in the eyes of the west ahead of hosting the G8 summit that year. “I can’t wait for the Tories to start looking at Portland’s lobbying for the Russian government,” one Labour source said.

The political role is separate from that of David Dinsmore, a former editor of the Sun who has been tasked with improving the civil service communications operation. There have been questions internally over whether either man is up to speed with the modern media landscape.

James Lyons, Downing Street’s director of communications for strategy, is stepping down. Steph Driver, his counterpart for day-to-day No 10 communications, who is close to Starmer, stays in post, answering to Allan. Joe Dancey, the Labour party’s director of policy and communications, and partner of the health secretary Wes Streeting, has also left his role.

The No 10 policy unit is also undergoing changes, after some internal conflict over who was running the department. Liz Lloyd, who was Tony Blair’s deputy chief of staff at No 10, is leaving but is expected to move to a new role in government.

Stuart Ingham, another policy chief and Starmer’s most longstanding aide, will leave the unit to work in chief of staff Morgan McSweeney’s team, taking on a more political role, which sources said would ensure the prime minister’s priorities were taken into account in every decision.

A new political policy chief is expected to be appointed shortly, but in the meantime Vidhya Alakeson, one of McSweeney’s deputies, will oversee day-to-day policy work.

However, there was some concern among Labour MPs that the changes may not fix fundamental problems at the top of government. The latest appointments mean that since Starmer became Labour leader, he has had four chiefs of staff and five directors of communications.

One Labour backbencher said: “Overall I think it is not something you can staff your way out of. This is about the politics and the story we tell. All the comms and strategy people in the world won’t fix that.”

A senior Labour source added: “It’s not just a question of narrative. It’s ‘what is our purpose and how do we use power?’ The stakes are a shift to radical right authoritarian government. As progressives that’s an emergency.”

In his BBC interview, Starmer said while he understood people’s concerns about migration, Reform and Nigel Farage were exploiting the issue. “They feed on grievance. They don’t want the problem solved because they’ve got no reason to exist if the problems are solved,” he said.

When asked about a recent spate of English flags being draped on lamp-posts or spray-painted on roundabouts, the prime minister said he was proud of the flag, and had one in his Downing Street flat, but was wary of it being used for “divisive” reasons.

Mujtaba Rahman, of political analysts Eurasia Group, said: “Keir Starmer’s reshuffle of his Downing Street team reflects his frustration at what he sees as a bloated but slow civil service machine and a desire to bolster No 10’s heft on the economy.

“That is a belated recognition that Starmer delegated too much power to Rachel Reeves, whose political judgment was lacking on means-testing the pensioners’ winter fuel allowance and welfare cuts – both later abandoned.”