Sir Keir Starmer has admitted that his pledge to make Britain number one for economic growth among G7 nations will be “tough” to achieve if Labour wins power at the next election.

The Labour leader on Thursday unveiled five “missions” setting out his administration’s objectives if voters hand him the keys to 10 Downing Street.

The five missions, which he said would look to “fix the fundamentals” and “restore pride and purpose” to Britain, will include securing the highest sustained growth in the G7 and building an NHS fit for the future.

This is the big fixing the fundamentals to make sure we can restore the pride and purpose to Britain

In a speech in Manchester today, Sir Keir will also set out ambitions to make Britain’s streets safe, break down the barriers to opportunity at every stage and establish Britain as a clean energy superpower.

The economic pledge would mean the UK outstripping the US, Germany, France, Italy Canada and Japan in terms of growth, something he conceded “is going to be tough”.

The opposition leader told BBC Radio 4’s Today programme: “Nobody is going to say, ‘That’s vague, that’s something that is going to be easily achievable’.”

On his pitch for Britain to become a green energy superpower by having clean electricity by 2030, he said: “Again, that is a sharp intake of breath.

“When I speak to CEOs and others about this, they say, ‘Mmm. That’s going to be going some, Keir’.”

With an election potentially a little over a year away, party officials said the “mission” plan will form the backbone of Labour’s manifesto.

Over the coming months the party will set out a series of “measurable ambitions” for each mission, beginning in Thursday’s speech with its plan for economic growth.

The former director of public prosecution said his approach was about doing away with “sticking-plaster politics” and dealing with the “everyday frustrations that people have that almost nothing seems to be working”.

He said the NHS and energy sectors needed solutions to take them out of the annual cycle of battling winter crises.

Sir Keir told BBC Breakfast: “We can’t just go on every year doing the same thing. We need something which is longer term.

“So this is the big fixing the fundamentals to make sure we can restore, if you like, the pride and purpose to Britain, the great potential that our country has.

“They are long-term missions, they are a statement of intent to how we intend to govern.”

In his speech, Sir Keir is expected to state that he wants a different approach to government, with neither state control nor pure free markets, but instead a “sleeves rolled-up” partnership working in the national interest.

Having led the Crown Prosecution Service for five years before becoming an MP, Sir Keir said his past experience had taught him that a holistic approach was required for dealing with issues such as crime.

He told Today: “If you want to reduce crime, you have to get to grips with your education system, you have to recognise the mental health element to it, you have to recognise the health element.

“You have to recognise that the single biggest indicator of whether someone is going to end up in prison is whether they had difficulties at primary school and whether they were excluded at secondary school.

“To get to the bottom of that problem, you’ve got to have cross-cutting.”

Asked how voters could trust his five missions given some on the left of his party have accused him of dropping pledges that won him the 2020 leadership race, Sir Keir said they “haven’t all been abandoned by any stretch of the imagination”.

He argued instead that his promises had to be adapted following the Covid pandemic, the outbreak of the Ukraine war and the economic fallout after former prime minister Liz Truss and former chancellor Kwasi Kwarteng’s mini-budget.

Sir Keir is expected to use his address to contrast his mission-led programme with the perceived short-term nature of Rishi Sunak’s five priorities in the run-up to the next election, which the Prime Minister set out in his new year address.