The arch-charlatan that is Boris Johnson made an out-of-character foray into truth-telling this week when he pointed out that countries such as India have traded more successfully with the EU than the UK has since the single market’s inception. As someone who voted ‘Remain’, and who retains intense feelings of unease about what will happen next, this datum struck a chord with me at the very moment that Theresa May is trying to claim the mantle of patriotic, swashbuckling Britain.

There is something of a self-fulfilling prophecy about Britain’s decision to leave the EU. The ‘Leave’ campaign repeatedly argued that the EU was doomed and that Britain ought to desert the sinking ship, rather than go down with it. Now that we are embarking on Brexit, that prophecy seems far more likely. As the EU’s second-largest economy, Britain is removing a supporting wall from the crumbling old house. With nationalists on the march in France and Germany, either Frexit or Grexit would almost certainly spell doom for the EU project.

It is difficult to predict whether Britain as a whole will be permanently poorer as a result of Brexit. The IMF has certainly been bullish about Britain’s prospects (although we remain in the EU at this point). As many Britons know to their cost, benevolent economic statistics in a chancellor’s budget do not necessarily translate into healthy pay packets or manageable prices at the shops. The economic consensus is still that Britain – and particularly, ordinary British people – will be significantly poorer in the next few decades as a result of Brexit. This will likely be exacerbated by coming out of the single market, as I argued earlier this week.

But we are where we are. What’s more, following her cleverly-crafted Brexit speech earlier this week, Theresa May has the whip hand over those advocating a soft Brexit. The Prime Minister may be a third-rate leader whose goose will be cooked by Tory backbenchers before long, but whoever is writing her speeches is certainly an adroit tactician with their finger on the pulse of the British people. There was a a Labour leader at the end of the last century who had a similar talent in his early days, but he has long since ceased to influence British affairs.

So Labour ought to stop following the narrative on Brexit and start shaping it. One of the highest-profile political victims of Brexit – George Osborne – recently said of the tragedy of Aleppo, “If you do not shape the world, you will be shaped by it.” I am far from a fan of Osborne, but there was a good deal of sense in this pronouncement. Right now, Labour is allowing itself not only to be shaped by Brexit, but to be split asunder by it. Brexit will dominate the next ten to twenty years of British political history, so we better find the answer to the riddle, and fast.

That answer begins will a call for progressive patriotism. This was the nom du jour of Labour’s greatest prime minister, Clement Attlee, who fought on both the eastern and western fronts in the First World War. While he was a true socialist, he was a patriot, too. He bought into the idea of Britain shaping the world in the nuclear age, not merely shrinking away from it. He did this in the wake of a far more seismic shift in Britain’s global standing – that which was brought about by the Second World War.

So Labour will need to find a way to advocate for British jobs and new British technologies and industries in post-Brexit Britain. Sooner or later, when the EU falls and working people will find that they have been betrayed by a Prime Minister who has no concern for their aspirations. When that time comes, Labour will have to be ready for a plan to devolve power and wealth away from the south east and into the regions that voted so overwhelmingly for Brexit. That, after all, is what ultimately lay behind their decision to kick the establishment and London in the face.

It is no use Labour bleating about Brexit or complaining that Mrs May is not thinking things through. Strength responds only to strength. Last night, the British Army practised moving tanks on rail through the Channel Tunnel in case they needed to deploy to eastern Europe quickly. Meanwhile, a British photographer photographed American Air Force jet duelling with a copy of a Chinese jet over Area 51, practicing combat moves. In the coming age of extremes, Labour must be the party of progressive patriotism, or it will be deservedly swept aside.

Sam Stopp

Sam Stopp is a Labour councillor in the London Borough of Brent and is the Chair of The Labour Campaign to End Homelessness. He has written regularly for LabourList, LeftFootForward, Progress Online and Open Labour. He tweets @CllrStopp.