It’s been a slow start, but in England devolution is finally taking off. Manchester recently became a source of envy for Britain’s many other “second cities”, after chancellor George Osborne announced he would grant the extended metropolitan region greater control over housing, transport and even health – all under the thumb of a democratically-elected mayor.

It’s a move which has been welcomed by many, not least because it helps bridge the ever-widening gulf between London and the rest of the UK. Scarcely a single other country in the Western world concentrates its power, wealth and culture so heavily in its capital. But critics argue that a mayoral system is a poor solution to this rising disparity; many fear it could lead to over-centralisation of power within those cities.

So do mayors actually help? In the UK, the honest answer is that we don’t really know. In 2012 Bristol became the one of the first handful of British cities outside of London to vote for a mayor, electing independent candidate George Ferguson to the new role. 

Now, researchers from Bristol’s two universities have analysed the new mayor’s impact on how the city is governed, and the findings are pretty revealing.

Before Ferguson came to power, less than a quarter of Bristolians felt the city had visible leadership. But by 2014, this had jumped to 69 per cent; among leaders from businesses and communities it leapt up to 97 per cent.

“It is entirely beyond doubt that the mayoral model of governance increases the visibility of city leadership,” said co-author David Sweeting of the University of Bristol. “After the introduction of mayoral governance, 54 per cent of citizens agreed that a directly elected mayor had improved the leadership of the city.”

The feedback from civic leaders was even more positive: 76 per cent of them felt leadership had improved under the new system.

The key stats from the research.

Part of this success has to be credited to the mayor himself. Best known for his eccentric red trousers, Ferguson has successfully styled himself as the ideal mayor for his eclectic city: independent from Westminster and the murky world of party politics; only wanting the best for Bristol.

His grand ambitions for the city have generated huge attention, both nationally and abroad. During his two-and-a-half year tenure, Ferguson has been hailed as Britain’s “most well-travelled” mayor, raising Bristol’s profile and helping it join the 100 Resilient Cities network and becoming European Green Capital 2015. Within the UK, Bristol has enjoyed unprecedented access to senior government figures – including multiple meetings with the Prime Minister.

But while the clear, accountable leadership has contributed to Bristol’s newfound fame, many residents feel it masks deeper problems; locals still have shockingly little confidence in the council’s decision-making.

“Only 3 per cent of councillors think that the introduction of the mayoral system has improved public confidence in decision-making in the city,” said Sweeting. “Citizens do notice a marginal improvement in trust, but it remains low – up to 23 per cent from 19 per cent.”

The tension between the mayor’s office and his councillors has been made clear in the report. Only 19 per cent of councillors now feel they can get involved in important decision-making – compared with 61 per cent before Ferguson came to power. In contrast to community and business leaders, many councillors feel power has been overly centralised in the mayor’s hands.

All this takes some of the shine away from Bristol’s newfound status – and from mayors in general.

“While many feel that the clarity of decision-making has improved,” said co-author Robin Hambleton, “evidence around timeliness of, trust in, and confidence in decision-making do not offer much encouragement for those who advocate the virtues of mayoral governance.”

Perhaps mayors aren’t the silver bullet in Britain’s attempts to devolve power. But the authors advise that, with a bit of tweaking, the mayoral system can still be made workable:

“Bristol and other mayoral cities can reduce the centralisation inherent in the system by devolving more decision-making power to councillors and involving neighbourhoods within the city more fully in decision-making processes.”

Britain’s mayors are only just getting their hands on power – but if they’re to use it well, we may need to force them to pass some of it on again.