The way the country is governed “must change” or Britain’s future could be at risk, the shadow levelling-up secretary is expected to say.

Lisa Nandy, in a speech at the Convention of the North on Wednesday, is due to outline Labour’s proposal to unleash the “power of all people in all parts of Britain” by handing Westminster controls to local communities.

She will accuse the Conservatives of having “written off” areas that once fuelled the UK economy and failing to deliver on the 2019 manifesto pledge of creating opportunities outside of London and the south-east of England.

Ms Nandy is expected to say in Manchester: “Ambition is everywhere in the towns, villages, and cities that were once the engines of Britain, for too long written off and written out of our national story.

“For 15 years, since the global crash, the failure of running an economy like this has been plain to see.

“But every time the public has sounded the alarm, hitting our politicians with tsunami after tsunami of discontent, our creaking political system has done nothing.

“This is the collective task facing our generation of political leaders: to respond to that siren call or face obsolescence. To change or die.”

The shadow cabinet member will urge local leaders to tell Labour what powers they need to drive growth in their areas as part of what Opposition leader Sir Keir Starmer has called his Take Back Control Act.

Ms Nandy said the legislation, described as the centrepiece of the first King’s Speech under a new Labour administration, would look to “empower our communities to take control of their own economic future”.

The Wigan MP will tell the conference that her party, should it win the next general election, would carry out its commitment to hand over powers in a wide range of policy areas, including housing, energy, childcare, buses, trains, skills, training and employment.

Party officials said Ms Nandy will describe the current funding model for local government as “absurd” and “undemocratic”, with the system replaced by a “significant expansion of economic devolution in England” during a Starmer premiership.

Vowing to “end a century of centralisation”, Ms Nandy will promise to “bake” that pledge “into our first two terms of government”.

Ms Nandy will say: “Unleashing the power of all people in all parts of Britain is no longer a ‘nice to have’, a local or a regional issue — it is at the heart of whether this country has a future or not.”

Labour is currently the frontrunner to lead the next UK government, with Sir Keir’s party about 20 points ahead of Rishi Sunak’s Conservatives in most opinion polls with an election less than two years away.

Levelling-Up Secretary Michael Gove is also scheduled to speak at the same event on Wednesday.

A Department for Levelling Up, Housing and Communities spokeswoman said: “We have overseen the greatest transfer of power from Whitehall to local leaders across England in modern times.

“This includes agreeing six landmark devolution deals, such as with the North East and York and North Yorkshire, unlocking more than £4.5 billion in new investment for seven million people.

“More than 50% of England will now be covered by a devolution deal meaning they have a greater say in the local issues that affect them such as housing and skills.”