Why are city mayors back on agenda?

The new plan for an elected mayors is for larger areas, such as Greater Manchester

Two years ago, the dream of having elected mayors running all of England's biggest cities suffered an abrupt and, some might say, devastating setback.

Voters in Birmingham, Leeds, Manchester and Newcastle were among those to give the idea a decisive thumbs-down in referendums in May 2012.

The people, it seemed, had spoken, and the electorate had shown itself deeply suspicious of the idea of introducing a new gang of elected politicians on comfortable salaries.

But on BBC Radio 4's Today Programme, the chancellor put elected mayors right back at the heart of the government's plans for rebalancing the economy and devolving power.

George Osborne said: "You need to see strong city leadership. I think there's a strong case for elected mayors in places like Greater Manchester."

Ministers will claim that their support for elected mayors never went away. They said two years ago that the process might be an evolution rather than a revolution.

This fresh intervention by the chancellor was, his officials say, "the beginning of a new conversation". No detailed plans have yet been drawn up for fresh referendums, or other ways of establishing mayoral structures.

There are already elected mayors in London, Leicester, Liverpool, Bristol and Middlesbrough. Supporters of elected mayors hoped other cities would see the success that individuals have had in these places, and eventually demand the same for their home towns.

Those who have argued consistently for city mayors felt that the referendum campaigns of 2012 were a huge missed opportunity - underfunded, underpowered and denied the full support of the main parties (because of internal divisions on the issue).

Part of the problem then was also the resistance of some in local government. Many local councillors were opposed to elected mayors from the start. Some feared a challenge to their powers. Others said "why change a system that's working"?

But as the economy of London and the South East once again starts to surge ahead, the campaign to push powers out to the cities of the midlands and the north is gathering momentum.

The looming Scottish referendum is also once again thrusting the issue of devolution in England onto the agenda. Cities are joining forces to demand a significant review of public spending and decision making - and with it the autonomy to drive their own local economies.

Government officials want to highlight two things that have changed in their approach since 2012.

Firstly they want to link elected mayors with the specific new powers these mayors will have - for example over transport and infrastructure spending. Secondly they emphasise that mayors will have to govern the entire urban conurbation - hence the emphasis today on Greater Manchester rather than just the City of Manchester.

London Mayor Boris Johnson and New York Mayor Michael Bloomberg wield widespread power

Many of the most dynamic and prosperous urban centres in the world have elected mayors, with significant rather than ceremonial power.

So the question will now be posed again - did the referendums two years ago fail because of a chaotic, underfunded campaign? Or are voters in these cities deeply and fundamentally opposed to the principle of elected mayors?

If ministers really do want to give this idea another big push, they will have to think carefully about the lessons of the failed referendums of 2012.