The evidence that investment, decision-making and oversight at this sub national level was linked to improved local economic outcomes was “mixed and inconclusive”, it added.

In a report, Progress in setting up combined authorities, the watchdog did acknowledge that the Department for Communities and Local Government had worked “speedily” to make sure combined authority areas were ready for the mayoral elections in May 2017.

It also accepted that there “is a logic to establishing strategic bodies designed to function across conurbations and sub-regional areas, and there is a clear purpose to establishing combined authorities especially in metropolitan areas, as economies and transport networks operate at a scale greater than individual local authority areas.”

The report also found:

There was a risk that local councillors would have limited capacity for the overview and scrutiny of combined authorities.

In May 2017, six mayors were elected to combined authorities in England, with candidates having campaigned on manifestos which frequently made policy commitments beyond the current remits of these organisations. “This raises the question of whether mayors can be credible local advocates if they only deal with the limited issues under the remit.”

Combined authorities were not uniform, and varied in the extent of the devolution deals they had struck with government.

If the United Kingdom’s departure from the European Union resulted in reductions in regional funding, the economic regeneration role of combined authorities would become more pressing. “Combined authorities are generally in areas which receive the most EU funding,” the NAO noted.

The NAO highlighted how a number of authorities had been unable to bring local authorities together to establish combined authorities, while areas with a long history of working together had often found it most straightforward to establish combined authorities.

“The capacity of most combined authorities is currently limited and the lack of geographical coherence between most combined authorities and other providers of public services could make it more problematic to devolve more public services in the future,” the watchdog warned.

The NAO’s recommendations were:

The DCLG should:

(a) continue to support combined authorities as they put in place their individual local plans for assessing their impact, including demonstrating the value they add;

(b) review periodically all frameworks and guidance in place for combined authorities and other bodies with joint responsibilities, to ensure that accountability for the delivery of services is clear to stakeholders in local communities; and

(c) continue to work with combined authorities as they develop sufficient capacity to:

deliver the functions agreed in the devolution deals;
support economic growth and the government’s industrial strategy; and
provide sufficient scrutiny and oversight to their activities.
Combined authorities should:

(d) work with the DCLG to develop their plans for assessing their impact, including demonstrating the value they add; and

(e) develop and maintain relationships with key stakeholders in delivering economic growth and public services in their areas.

Areas planning to establish combined authorities should:

(f) make sure they have and can clearly articulate a common purpose;

(g) form an area with a clear economic rationale, mindful of existing administrative boundaries; and

(h) develop relationships across areas where there is no history of joint working.