The truth of the past month is that a long-brewing crisis of our politics has finally erupted. It is not my job to pick over the reasons underpinning the Brexit vote; the British people have spoken, and their decision must be implemented in as coherent and orderly a fashion as possible.

Looking at the voting numbers which so painfully demonstrated the reality of a divided country, I was reminded of a piece I wrote a couple years ago on the potential role of cities and devolution in uniting the country. The Key Cities Group was created to advocate for increased powers to cities – not so that cities can go it alone, but because we believed that by empowering individual cities, you can create strong communities and thus build a better Britain. Indeed, I still believe that with greater powers to cities, we can have a more vibrant and united country, with prosperity more evenly spread.

Underlining this train of thought, IPPR North recently published an excellent report – City systems: The role of small and medium-sized towns and cities in growing the northern powerhouse – which highlights how cities like our members are critical to this effort. It serves as a reminder that we cannot let the political drama of the referendum fall-out and ensuing soap opera distract us from the good work we have embarked upon to spread economic development throughout the country through the devolution process.

The IPPR report provides a warning against adopting a uniform approach to devolution, on the assumption that only one kind of city can prove successful in a global economy. Instead, the report encourages us to view the success of different cities, not as some natural phenomenon in urban development, but as the product of deliberate public policy decisions.

London, for instance, was a shrinking city in decline for much of the 20th century – but its position in a new global economy, and new devolved powers unlocking huge investment in infrastructure, have seen it become a world success. Manchester has witnessed a remarkable renaissance in the last 20 years to become the centre of growth in northern England. We have to take the same attitude toward our mid-sized cities.

There is no reason, though, why they cannot also experience a remarkable turnaround. The IPPR report refers to several, interesting examples of how and where this has been achieved, and there are so many more mid-sized cities with huge potential. As the IPPR report emphasises, there is no correlation between population and productivity in the UK: indeed, as both IPPR and our own report with ResPublica last year demonstrated, mid-sized cities have seen their Gross Value Added (GVA) to the UK economy grow at the same rate as other cities since the recession almost 10 years ago. What we need is a change of mentality as much as anything else.

IPPR has recommended that Key Cities like ours invoke the entrepreneurial spirit, creativity, and energy of small & medium size enterprises (SMEs). IPPR has also recommended that we identify the role we play in wider urban ecosystems, both with larger cities, and with rural hinterlands who supply markets and workers. And it suggested that critically evaluate where our cities need more capacity and expertise at the local government level, if they are to play their part in shaping regional and national policy.

There is much merit in these suggestions, and they are worth pursuing. I would echo IPPR’s stress on the importance of connectivity – both between cities and between sectors, moving people, moving goods, and moving ideas which promote innovation.

We must cooperate with towns and districts around us, and with our partners in Core Cities to achieve our common vision. To do anything less is to accept that the reality of a divided Britain which we saw on 23 June will be here to stay.

Cllr Paul Watson is leader of Sunderland City Council and chair of the Key Cities group of 24 mid-sized cities.

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