Des McNulty and Anne Green ask why some English city-regions turn devolved powers into effective strategy while others struggle to get off the ground. Their answer revives and updates a decades-old idea from economic geography — institutional thickness — to explain the gap. This blog draws on their new working paper and accompanying policy briefing, produced through the Local Policy Innovation Partnership Hub.
A patchwork, not a rollout
Since the 2014 Greater Manchester devolution deal, England has built up a patchwork of metro mayors and Combined Authorities (CAs) rather than rolling out devolution evenly. By 2024, twelve areas had mayoral devolution, covering around 41% of the population (Institute for Government, 2024), and more have joined since. The English Devolution and Community Empowerment Act 2026 has now put a three-tier system of ‘strategic authorities’ onto a statutory footing, with an ambition that every part of England eventually reaches the top tier.
But statutory ambition and lived reality are different things. Greater Manchester and the West Midlands have built substantial governance capacity: in-house analysts, established relationships with Whitehall, and years of practice working together. Many newer and smaller Combined Authorities are starting from close to scratch. Why?
It’s not just money, and it’s not just organisations
The instinctive answer is resources: richer, better-connected places do better. But institutional thickness suggests something more specific is going on. First developed by Amin and Thrift in 1995 to describe successful industrial regions, and applied to UK local governance for the first time by Coulson and Ferrario (2007) in a study of Birmingham, the concept argues that what matters is not simply how many organisations: councils, universities, business bodies, exist in a place, but how well they work together: their pattern of interaction, and whether they share a genuine sense of common purpose.
Coulson and Ferrario’s finding, since echoed elsewhere (Rodriguez-Pose, 2013), was that Birmingham’s crowded governance landscape was a poor predictor of effectiveness. What mattered more was the quality of coalitions and, hardest of all to build, a genuine shared sense of common enterprise among very different organisations.
Splitting thickness into what’s visible and what isn’t
Our paper draws on Zukauskaite et al.’s (2017) influential refinement of the concept, which splits institutional thickness into two layers: a formal dimension (the organisations and partnerships you could put in a diagram) and an informal one (the trust, shared mental models and collaborative norms that make the formal structures work effectively). Places can look similarly ‘thick’ on paper while performing very differently in practice, because it’s the informal layer: invisible, slow to build, and easy for funders to overlook, that is doing the real work.
Putting people back into the picture
The other update we make is to bring agency back into a framework that has traditionally been quite structural. Grillitsch and Sotarauta’s (2020) ‘trinity of change agency’ identifies institutional entrepreneurs, alongside innovators and place-based leaders, as the people who build, sustain, and sometimes dismantle the relationships and norms that constitute institutional thickness. Gibney and Nicholds (2021) push this further, reframing leadership itself as ‘social purpose’: the capacity to articulate and hold together a shared direction for a place, rather than simply occupying a formal office.
This matters for one of the liveliest debates in English devolution: do you need an elected mayor to get things done? The evidence is mixed. Greater Manchester’s effectiveness predates its mayoralty and rests on a collaborative culture built by council leaders and officers over many years; Glasgow’s City Region Cabinet shows a similar pattern without any single mayoral figure. Individual leadership can accelerate the development of institutional thickness and raise a place’s visibility with central government, but it is not a substitute for it. Where a mayor crowds out others’ contributions, or a change of leader disrupts accumulated relationships, thickness can be eroded rather than deepened.
Why Whitehall is part of the problem
Crucially, institutional thickness in England is not simply something local actors build or fail to build. Central government’s own habits, including short funding cycles; forcing places into competitive bidding; frequent restructuring; and a persistent ‘Whitehall knows best’ culture, actively erode the relational capacity devolution depends on. Hoole et al. (2023) call this England’s ‘Catch-22’: devolution assumes strong local institutions already exist, while the system for delivering it undermines the very capacity it requires. Places with accumulated institutional capital, like Greater Manchester, have shown they can partially absorb this pressure; thinner institutional environments cannot, and the gap widens.
What this means as devolution speeds up
This framework matters right now because the pace of change is accelerating. The 2026 Act, the Treasury’s promised fiscal devolution roadmap, and Andy Burnham’s pledge to build a satellite ‘No.10 North’ function in Manchester all point towards faster, deeper devolution, a direction one assessment describes as an acceleration of an existing trajectory rather than a genuine change of course. Evidence from the first wave of mayoral devolution, meanwhile, found no faster-than-expected growth overall, with such gains as there were skewed towards already-wealthy districts within devolved conurbations. Some commentators go further, arguing the Treasury’s underlying caution about ceding fiscal control has barely shifted despite a decade of devolution. Speed without a parallel investment in relational and analytical capacity risks reproducing today’s inequalities more quickly, rather than resolving them.
Our policy briefing sets out what a more deliberate approach would look like: funding the informal as well as the formal side of institutional thickness; identifying and backing the people who do the less visible and frequently unacknowledged work of convening partners; targeting support by starting capacity rather than by prominence; and crucially reforming central government’s own behaviour as a precondition for, not merely a complement to, effective devolution.
This blog draws on Des McNulty and Anne Green’s working paper and accompanying policy briefing, ‘Place Capacity and Institutional Thickness: Leadership, Agency and the Governance of English Devolution’ (July 2026), produced through the Local Policy Innovation Partnership Hub.
This blog was written by Des McNulty, Chair of the Local Policy Innovation Partnership (LPIP) Advisory Board and Honorary Professor at Glasgow Caledonian University and Anne Green, Professor of Regional Economic Development and Co-Director of City-REDI, University of Birmingham.
Disclaimer:
The views expressed in this analysis post are those of the author and not necessarily those of City-REDI or the University of Birmingham.