Professor Michele Acuto, Professor of Urban Resilience and Pro Vice-Chancellor for Global Engagement, University of Bristol - Written evidence (MUL0021)

City Diplomacy for a Changing World Order

Michele Acuto is Professor of Urban Resilience and Pro Vice-Chancellor for Global Engagement at the University of Bristol, Editor-in-Chief of Urban Studies, and a Trustee of Fondation Botnar. He is a Fellow of the Academy of Social Sciences. He co-convenes the Australian Government-funded ‘city diplomacy masterclass’.

This submission builds on a working paper commissioned by the British Academy’s Global (Dis-)Order program.

Submission Summary

Q13. What are the core areas of UK policy that demand multilateral solutions and which therefore the UK Government should prioritise in the years ahead?  Additionally, in which multilateral policy areas are we playing to our strengths and therefore are likely to be the most influential?

1. This submission demonstrates that the rise of city diplomacy constitutes a significant development in contemporary geopolitics, and yet remains underappreciated in British foreign policy, requiring urgent prioritising.
2. The growth of city diplomacy is well-documented and should not be understood as a challenge to the state-based international system, but rather as an adaptive response to the growing complexity of global governance and the localisation of transnational challenges, and one that has already been effectively engaged by United Kingdom allies.
3. The United Kingdom is uniquely positioned to benefit from this trend. Its strong urban system, focus on devolution, global city networks, mayoral institutions, diplomatic reach, and experience in multilevel governance provide significant comparative advantages.
4. This area requires urgent action: cities are increasingly on the front lines of global challenges and national security threats, and, in turn, the above capacities and political momentum afford the United Kingdom a timely window for investment in national urban resilience.
5. The Government should therefore explicitly incorporate city diplomacy into foreign and security policy. This submission recommends establishing a dedicated Subnational Diplomacy Unit within the Foreign, Commonwealth and Development Office to leverage the full benefit and manage the range of challenges of this growth in city diplomacy.

1. Introduction

The international order is undergoing profound turbulence. Current geopolitical competition, institutional fragmentation, renewed great-power rivalry, and growing pressure on multilateral institutions is hard to navigate for states like the United Kingdom, and perhaps even more so for other layers of government. Yet, this challenging world order is also unfolding within a planetary context of global urbanisation, which has transformed the practical realities of global governance through one of its most tangible underpinnings. Urban issues and their inference on global governance should be readily understood in all multilateral debates. Most of the world's population, economic activity, infrastructure, innovation, and emissions are now concentrated in cities. 81% of humanity now lives in cities and towns, which together account for more than 60% of global GDP. As the United Nations put it, “urbanization is a defining force of our time.”[1] This global urban reality is increasingly recognised in the multilateral context: since 1972, cities and urban issues have been the object of at least 1246 formal acknowledgements in United Nations frameworks and treaties,[2] 43% of which ascribe direct roles to cities as active UN partners and participants. As a result, cities have gradually become accepted as actors in international affairs rather than merely objects of national policy or sites for global challenges. Yet, the significance of cities is frequently overlooked in national assessments of international order, not least in British foreign policy.

I argue here that the United Kingdom is instead uniquely poised to benefit from this trend. Its strong urban system, global city networks, mayoral institutions, diplomatic reach, and experience in multilevel governance provide significant comparative advantages. I outline this in relation to key questions in this call for evidence. Based on current scientific and global best practice, I recommend that HMG establish a dedicated Subnational Diplomacy Unit within the Foreign, Commonwealth and Development Office to strengthen the national purpose and capacity for city diplomacy. This would build on existing or past examples of international best practice but lead internationally. I outline this through three insights that respond directly to Q13 of this inquiry and welcome any further engagement with the Committee.

2. Insight One: The Rise of City Diplomacy is a Major Contemporary Trend in Multilateralism

Over the past three decades, cities have developed extensive international engagements through transnational municipal networks, participation in multilateral processes, international partnerships, climate alliances, migration initiatives, and direct cooperation with foreign governments and international organisations. This phenomenon — commonly referred to as "city diplomacy"— has become a durable feature of global governance.[3] The growth of city diplomacy is not a temporary phenomenon but a structural feature of twenty-first-century international relations.[4] This evolution reflects a broader transformation in multilateralism itself: effective international cooperation increasingly depends upon actors operating below, or transnationally to, the level of the sovereign state. The evidence of this is clear. Today, there are more than 200 networks of cities operating internationally with explicit engagement through the multilateral system, and over 100 operating nationally as a clear aggregator of urban action within countries around the world.[5] In an average year, there are over 500 international events and summits centred on cities. UN agencies and multilateral funding agencies have dozens of multilateral programs focused on, or partnered directly with, local governments. City diplomacy is often present even in contexts of retreating states. For instance, major cities in the United States are still closely engaged in climate action or migration. Yet, the emergence of city diplomacy should therefore be understood not as an alternative to statecraft, but as a durable adaptation of the international system to the realities of urbanisation, interconnected economies, and increasingly localised implementation of global commitments.

3. Insight Two: Engagement with City Diplomacy Offers the UK a Strategic Advantage

Importantly, city diplomacy should not be interpreted as a replacement for traditional diplomacy. Rather, it represents an expansion of the ecosystem of international cooperation. Cities increasingly provide additional channels through which international coordination can occur. The changing international environment creates opportunities for the United Kingdom to leverage city diplomacy as a strategic asset and work more effectively with its city diplomats internationally.[6] The evidence increasingly suggests that cities can sustain international cooperation during periods of geopolitical tension because they remain focused on practical, everyday governance challenges that are directly graspable to their urban constituents, while also participating in multilateral policymaking. For instance, the hundred members of the C40 Cities Group have delivered tens of thousands of practical municipal actions since its launch in London in 2005.[7] These are shaping the lives of billions of urban dwellers, with city diplomacy turning into practical municipal policy through bus fleet electrification, tree canopy expansion, clean energy solutions, and waste management innovations.

Hence, in a more fragmented international order, cities can function as channels for continued international engagement, with the advantage of direct implementation capacity. City leaders are often perceived as ‘closer’ to the everyday view of an elector than diplomats and national policymakers. In turn, if not properly embedded and understood within the foreign policy apparatus of states, city diplomacy risks para-diplomatic dissonance that diverges significantly from the national interest, enhancing central-local tensions,[8] or creates an urban ‘minilateralism’ that undermines the multilateral system.

For the United Kingdom specifically, this opportunity is particularly significant. The current Number 10 emphasis on devolution and on empowering local authorities is perfectly aligned with the purpose of city diplomacy. The UK possesses a distinctive comparative advantage in the emerging landscape of subnational diplomacy. Few countries combine: a globally connected metropolitan system; internationally recognised city leadership institutions; strong diplomatic and consular networks readily linked to strong national urban networks (Core Cities, Key Cities); deep experience of multilevel governance; and significant soft-power assets concentrated in urban areas. London remains one of the world's foremost diplomatic, financial and cultural hubs, while the UK's network of combined authorities and metro mayors provides an increasingly visible layer of internationally engaged leadership. Yet this is not just a global city story. Internationally, over 10,000 local authorities engage in city diplomacy.[9] In the UK, major hubs are recognised in their city diplomacy, including Birmingham for sports and European policy, Bristol for migration and energy, and Glasgow for climate and culture. The UK has the unique advantage of increasingly close engagement by Combined authority Mayors with Number 10, and a clear edifice of technical expertise through entities such as the Centre for Cities and the LGiU, alongside solid training in diplomacy through the FCDO International Academy. Earlier HMG regonition for this area also foreground the value for a now urgent re-investment.[10] Indeed, cooperation with allies such as Australia, France, or Japan on this front would be easy. The rationale is straightforward. These assets position Britain to become a leading practitioner in multi-level statecraft.

As geopolitical competition intensifies, cities increasingly sit at the front lines of strategic challenges, including infrastructure resilience, foreign investment screening, supply chain security, migration management, climate adaptation, cyber risk, and foreign interference. Urban issues are increasingly national security issues. A significant proportion of cyber security threats and attacks are increasingly centred on urban infrastructure and local administrations, such as those in Leicester and London in 2024. Cities have historically been the main theatres of epidemics and pandemics, and they also increasingly act as major theatres of new warfare tactics.[11] Yet engagement between central government foreign policy institutions and local government remains relatively ad hoc. A more systematic approach would provide Whitehall with enhanced situational awareness, stronger domestic resilience and additional channels of international influence. It is urgent for the UK to recognise the need to invest strategically in this tactical capacity. With the United States' faltering investment in this area, the UK could position itself as a leader and deliver a leading program of city diplomacy ahead of allies and the wider international context, at a moment when many states remain focused exclusively on traditional interstate approaches.

4. Insight Three: City Diplomacy can be effectively institutionalised to deliver greater capacity for the United Kingdom in a changing world order

Current geopolitical trends suggest that the future international order will be characterised less by a single dominant system and more by overlapping institutions, regional coalitions, and plurilateral arrangements. In such an environment, flexible and issue-specific forms of cooperation become increasingly important. Leveraging city diplomacy purposefully allows a state to drive multilateral cooperation on a whole additional scale, pace, and form compared to that provided by traditional foreign policy. Cities have repeatedly demonstrated their ability to maintain practical relationships across political and ideological divides. Urban cooperation often persists even when national diplomatic relations become strained because cities share common challenges relating to infrastructure, economic development, housing, climate adaptation and public services.

City diplomacy should be viewed as a complementary layer of international engagement that enhances national diplomatic capacity rather than competing with it. Several allied governments have already experimented with institutionalising subnational diplomacy as an element of national foreign policy. Countries like Germany, France and Japan have all been experimenting with various ways of leveraging city diplomacy. For instance, Japan and France have facilitated the access of cities to G7 proceedings via an ‘Urban 7’. The United States established a Special Representative for City and State Diplomacy and created a dedicated Subnational Diplomacy Unit within the Department of State (both 2022-2025). The Unit coordinated engagement between federal diplomatic institutions and governors, mayors and local authorities, and managed a city placement program for State Department diplomats to enhance local capacity – the Lewis Fellowship program. The Unit's formal mandate included developing strategies and policies for engagement between the Department and subnational governments.[12] Similar initiatives can be observed elsewhere. France has long supported "territorial diplomacy" through dedicated national coordination mechanisms. Since 2021, Australia’s Department of Foreign Affairs and Trade has funded a bespoke training program in which we work to de-risk how we engage with China and to build capacity in local governments to engage directly with China.[13] This is allowing countries like Australia, France, and the United States, previously, to proactively redress asymmetrical diplomatic engagements between foreign entities like China and their own local governments – an area the UK currently lacks capacity in. In turn, China’s grasp of this capacity shows significant understanding of the dynamics of urbanisation in its foreign policy apparatus, as in the context of the Belt and Road Initiative, as well as in leveraging the projection of national interest and public diplomacy by its major cities. The result is a growing recognition that subnational actors can complement rather than compete with national foreign policy.

5. Recommendation: Establish a Subnational Diplomacy Unit within the FCDO

The principal recommendation arising from this evidence is that the United Kingdom should consider establishing a dedicated Subnational Diplomacy Unit within the Foreign, Commonwealth and Development Office. This could build on the State Department experience, with a recognised lead (e.g., at Director or Director General level), and run a Lewis Fellowship-like scheme to place mid-career FCDO-experienced staff to support capacity building and familiarisation in local authorities across the UK. This could be effectively delivered in coordination with Combined Authorities, Core Cities and Key Cities, and potentially effectively tested in a pilot run in the former.

A dedicated unit would:

1. Facilitate Strategic Coordination. The Unit could act as the principal interface between FCDO, devolved administrations, mayors and local authorities on international affairs. The unit could develop systematic relationships with global city networks and urban-focused multilateral program organisations, some of which are already funded by the UK. The unit would provide the Government with specialist expertise on urban geopolitics, city networks, subnational diplomacy, and the role of metropolitan regions in international affairs.
2. Support UK Cities' International Engagement. The Unit could provide guidance on foreign partnerships, overseas investment relationships, strategic risks and foreign interference affecting local authorities. The unit would assist UK cities and devolved administrations in navigating international opportunities, partnerships, and risks while ensuring coherence with broader national objectives. It could also leverage the FCDO network, connect British diplomatic posts overseas with local and regional authorities pursuing international engagement and vice versa.
3. Build Foreign Policy Capability. The Unit could facilitate, in collaboration with expert and trusted partners, the development of training programmes for local officials on international engagement, geopolitical risk, and strategic partnerships. It could also work two-way, by facilitating intelligence and training to strengthen the UK’s Foreign Policy and Defence apparatus to better grasp urban issues as theatres of geopolitics, actors in subnational diplomacy, and pathways to foreign influence, but also to national risk.
4. Strengthen National Security and Resilience. The Unit would improve engagement between the diplomatic apparatus and local government, enhancing national situational awareness and resilience. The unit would allow FCDO, Home Office and Department of Defence to better assess and engage with a critical pathway for foreign influence and non-traditional security threat management grounded at the local level of government.

Such a unit need not constitute a significant new bureaucracy or sizeable financial commitment. The United States Subnational Diplomacy Unit operated with a relatively small staff complement, providing a focal point for coordination across government and relying in trusted partners to deliver insights, training and facilitated engagement. A UK equivalent could initially be established through a modest reallocation of existing FCDO resources, delivering disproportionate gains in influence, resilience and policy coherence.