Last Thursday was the biggest moment in England’s unfolding devolution story, with metro mayors elected across the country’s largest urban regions. The 12 mayors now in office – plus four being created in 2025 – will control £30bn or more of public spending and will form a powerful coalition making the case to the next government for more powers and investment.

Managing the relationship with the mayors will be a challenging task for whoever is prime minister this time next year, but getting devolution right could be key to tackling the economic underperformance of England’s cities and regions away from London.

Devolution has already empowered local leaders to take control of key economic levers – such as transport, skills and housing budgets. But the job is half done at best, and the next government has the opportunity to put in place a long-term devolution settlement for England as a whole.

As a new Institute for Government report argues, the government formed after the general election should extend devolution to all of England’s remaining large urban areas, including Portsmouth, Reading and Stoke. It should expand the current ‘trailblazer’ deals on offer to Greater Manchester and West Midlands, for instance by including control of employment support funding, and offer similar deals to other places including the new North East mayoralty.

As devolution is deepened, further attention should also be paid to governance and accountability issues. Investment is needed in new scrutiny mechanisms, data science and analytical capability, and policy evaluation exercises so places can learn from each other about what works. Finally, devolution should be given a firmer constitutional footing: for instance, the prime minister should hold an annual summit with all metro mayors to  make clear that they are key strategic partners of government.