Andy Burnham officially became Britain's new prime minister on Monday after years of political experience shaped both in Westminster and as mayor of Greater Manchester.

After nine years as a popular mayor of Manchester and earning the moniker "King of the North," Burnham has brought his own priorities and values to the national stage – a vision of expanding nationwide what has been achieved in the northwestern English city.

His political approach has focused on decentralizing power, strengthening regions and creating a more balanced economy across Britain.

From Westminster insider to 'King of the North'

As Burnham began his premiership, he has started to shrug off the joke that framed his early career in Westminster: "A Blairite, a Brownite and a Corbynite walk into a pub. 'What would you like, Andy?' asks the barman."

The 56-year-old first entered Parliament in 2001 and later served in senior government roles, including as Secretary of State for Health, representing different strands within the Labour Party before leaving Westminster in 2017.

But it was his move to local government that reshaped his political identity.

After becoming the first elected mayor of Greater Manchester in 2017, Burnham spent nine years leading the city region and earned the nickname "King of the North." His focus on improving transport links, expanding urban housing, investing in new industries and knowledge-based growth became the blueprint for his national agenda.

Greater Manchester was an early beneficiary of devolution, gaining greater powers and resources from the central government. During Burnham's tenure, the region attracted investment and partnerships with private companies, while Manchester's GDP expanded by about 3.1% annually on average in recent years, around twice the rate of the UK over the same period.

His approach, often described as "Manchesterism" or "Burnhamism" and labeled "business-friendly socialism," is built around the idea that Britain's highly centralized system should give more power to local and regional governments to drive growth more fairly and efficiently.

In outlining his agenda for government, Burnham has pledged to "rewire" the state, with plans including decentralizing power, taking key services into public ownership, creating more training and job opportunities for young people and building more social housing.

'Making everyday life easier'

Alongside his long-term plans for economic reform, Burnham has said his government's top priority is to tackle the cost of living and make everyday life easier for people.

The phrase has become one of the newer themes in his political messaging, reflecting his focus on easing the pressures facing households, particularly on everyday costs.

Burnham has argued that government should not only pursue long-term growth but also help people feel immediate improvements in their living standards, including through stronger public services, greater economic security and support for communities facing financial pressures.

Hard power

Beyond Britain's shores, Burnham's views are largely unknown and untested, but he has linked national security with his domestic economic vision.

He has called for building "a Britain that is more resilient, confident and principled."

He says Britain must use defense and other sectors to reindustrialize, and "generate economic growth and create apprenticeships and jobs in communities that have seen opportunities drain away."

He also calls for "reducing foreign dependency, securing inward investment and building new industrial partnerships with allies" and strengthening ties with European countries.

"Reindustrialisation through defence – and other sectors – is critical for both our economic and national security, building resilience in all our places. It will be a core priority for me," he writes.

It is also notable that one of his closest advisers is Jim O'Neill, the economist who famously coined the term BRIC and has been a strong proponent of the localizing agenda Burnham has put at the core of his politics.

O'Neill has suggested that the UK needs to rely less on the United States and strengthen ties with developing economies. He added that Britain "should be open to increasing its trade with countries like China."

A national test

So what will Burnham do in office? On specifics, many questions remain.

But as he takes charge of the country, his ambition is clear: localize, take power from the center, give cities and regions the chance to become stronger economic cores, and in doing so make Britain a more equal and resilient country.

At the same time, his ability to deliver immediate improvements to people's everyday lives will be closely watched.

"Imagine" was a theme running through Burnham's keynote speech on his vision for the country – now his ideas are being tested on a much bigger scale.