James Palmer is the Mayor of Cambridgeshire and Peterborough.

If one of the great hopes for the UK, post-Brexit, is unshackled free and fair trade with the rest of the world outside of the EU customs union, then we must also think about how best to put our economy in the international shop window.

Cambridgeshire and Peterborough itself is well placed to benefit from broader international trade, hosting 25 of the world’s biggest companies, being home to one of the largest centres for life sciences on the planet, and being part of the UK’s answer to Silicon Valley: Silicon Fen. We also have a university and research base which is the envy of the globe, feeding our innovative enterprises. My Combined Authority area contributes £5 billion to the Treasury annually, and growing.

My vision is for Cambridgeshire and Peterborough to be known as the UK capital for innovation and productivity, and in any post-Brexit arrangement, we need to be promoting our pioneering regions to the globe. But who is best placed to do that?

I have recently returned from a week-long visit to Boston, Massachusetts for a range of engagements with politicians and business leaders from across the world, and my experiences have left me in no doubt about the role this country’s Metro Mayors can play in fostering economic bonds with other nations.

This is more than just thinking aloud. While I was in Boston I signed an agreement with Marc McGovern, the Mayor of Cambridge, Massachusetts, to work towards a Partnership Accord between our two centres, which will strengthen our economic ties and grow trade and investment between us.

I cannot think of an international partner more appropriate to my area than Cambridge, MA. We’re both world leaders in life science, homes to thriving tech clusters and between us are home to three of the greatest universities in the world, Cambridge, Harvard, and the Massachusetts Institute of Technology.

Cambridge, MA is part of the greater metropolitan area of Boston and it is well known for its Kendall Square business district, described as one of the most innovative square miles of enterprise on the planet thanks to its quantity of creative and pioneering businesses based there. It has 200 life sciences-related companies as well as 80 venture capital firms, which are helping to fuel the innovation economy.

Meanwhile our Cambridge has 4,500 knowledge-intensive businesses within 25 miles of the city and its enterprises file more patents than the next four best UK cities combined. The University of Cambridge is recognised as the world’s second best, and the city can boast 98 Nobel Prize winners. Furthermore, with both centres offering a similar business climate, several major corporations including Microsoft, Amazon and Genzyme to name a few, chose to have a base in both cities.

A full Partnership Accord between our two centres will see growth in mutual trade and investment, it will partner complementary businesses to share ideas and work on projects, and it can unite our world-class learning institutions to collaborate on ground-breaking research. The scope is exciting, and now we can add direct flights by carrier Primera Air from London Stansted to Boston into the mix, which I used personally for the first time for the trip and is just the service we need to strengthen our connections further. For those not familiar with the geography, Stansted is only a 30 minute car or rail journey from Cambridge.

But we do not just share similar strengths. Both Cambridge MA and Cambridgeshire and Peterborough face similar challenges. Both areas must balance their growth economies with building enough houses, alongside developing a mass transit system solution that works for everybody. I have already taken away many useful ideas on solving these problems, and we have pledged to work together further on these issues.

I know my fellow Mayors across the country are also forging links with international cities and regions that have synergies with their own. We know our own backyards, we know the strengths and challenges of our economies and we have that passion to make our regions better more prosperous places for the people we serve. That makes us ideal ambassadors to open doors to trade.

I was a reluctant Remain voter, but if we are ever to maximise the potential of Brexit, the UK needs to be able to forge its own trade deals. That can only be done successfully if we leave the EU customs union. Part of my role as Mayor will of course be about making sure that Cambridgeshire and Peterborough is best placed to manage the challenges that Brexit brings, but it will also be about being alert to the new opportunities that will come our way from overseas markets and investors.

Metro Mayors can play a crucial role, operating within those new trade deals, to foster localised trade agreements with certain cities, areas or regions, that have mutual interests with their own, anywhere in the world.

A Government cave-in on leaving the customs union risks not just a major deviation from the spirit of Brexit, but also binds us to the old way of doing trade. As Mayor, I’m so proud and ambitious for my region that I want to shout about it on the international stage. For that to result in meaningful investment coming into Cambridgeshire and Peterborough, I need a Brexit that allows this country a free hand to forge its own trading future, opening up areas like mine to the potential of the global economy.