Academics have long singled out Britain for high levels of regional inequality compared to other advanced economies, but the issue has gained new political traction in light of soaring inflation and collapsing public health and transport services.
Former prime minister Boris Johnson made "levelling up" Britain a flagship policy in 2019. While his successors have also vowed to tackle regional inequality, local leaders say there has been scant progress.
Mayors and civic leaders from the north of England, in a joint statement on Tuesday, called on London to "hard-wire" levelling up into British law, echoing Germany, where the constitution guarantees equivalent living standards.
"Germany shows us what can be done when you hard-wire legal guarantees to tackle inequalities and empower local leaders into the fabric of your country," said Andy Burnham, mayor of Greater Manchester.
"East Germany has seen long-term support and investment since the fall of communism - and it has worked. Cities in Eastern Germany are now powering ahead of cities here in the North."
A report on Wednesday from the think tank IPPR North showed the region - if it were a country in its own right - would rank second-bottom out of the 39 countries in the Organisation for Economic Cooperation and Development for generating investment, ahead of only Greece.
The northern leaders criticised Britain's current system for requiring towns and regions to bid against each other for the allocation of funds. Questions have also been raised by opposition lawmakers and academics about "pork barrel" ministerial interference in local funding decisions.
Residents in the vast majority of places outside of London feel their local area has declined in recent years, according to a YouGov poll published last week - a major challenge for Prime Minister Rishi Sunak, whose Conservative Party has been in power since 2010 and now trails in opinion polls.
Sunak has said levelling up will be defined by his government's action, and last week pointed to more than 100 local projects.
The minister for levelling up, Michael Gove, was due to address a "Convention of the North" in Manchester at around midday (1200 GMT).
His opposition Labour Party counterpart, Lisa Nandy, was set to tell the conference that her party would empower local leaders and "end a century of centralisation", according to excerpts of her speech.
(Reporting by Andy Bruce; Editing by Susan Fenton and Kevin Liffey)
By Andy Bruce
