Andy Burnham will take his first major step to putting Britain's utility companies into public control when, at the Labour conference, he announces a new government-backed body to invest in the electricity grid.
The prime minister will use his first speech as party leader to announce the creation of GB Grid, which will use money previously allocated to Great British Energy to compete with privately owned companies such as National Grid.
The announcement marks the first significant move towards delivering on his promise to put "the essentials of life" under public control – even as ministers wrestle with how to deliver on more radical policies such as nationalising Thames Water.
Burnham will tell the conference on Tuesday: "We have a cost crisis. We all know it. The price of energy is crippling for businesses, and British billpayers pay some of the highest energy costs in Europe.
"We have an energy system where prices are dictated in markets miles away, while families and businesses here shoulder the costs. Once again, the British public has lost control."
He will add: "Within 10 years, I want our energy costs to be in line with other nations in Europe. That means we must reform a broken energy market so it serves the public interest."
Burnham's first conference speech as leader and prime minister caps a remarkable turnaround in his political fortunes since this time last year, when he was criticised by many in the party for talking openly about his desire to replace Keir Starmer.
Having now ousted Starmer from office, Burnham has spent much of his first few weeks promising to undo what he calls "40 years of neoliberalism".
The creation of GB Grid is his first significant step to challenging the power of private companies to run Britain's infrastructure.
The organisation will be given access to a pot of £4bn that has already been allocated to the government-backed Great British Energy – although it is not expected to use all of that money.
With businesses complaining about how long it takes to get a grid connection for new buildings and projects, GB Grid will use the funding to build more connections, as well as to maximise and speed up the rollout of renewables across the UK. It will be the first publicly owned player in electricity networks since privatisation.
Officials said the government would also expand the rights of businesses to build their own connections, allowing them to tap GB Grid's funding to help pay for it – a move which they said helped speed up connections in Ireland by 11 months.
Speaking to the Guardian's Politics Weekly podcast on Monday, the energy secretary Miatta Fahnbulleh said: "One of my frustrations with the last government is that they didn't recognise the need to invest in the system, and so we're having to do that at record pace over the course of the next decade.
"It is incumbent on all of us to make sure we're doing it in the most cost-effective way."