Ever since Keir Starmer announced in opposition the intention to “reconnect” Britain to continental Europe, a question has lurked. Is this in essence a “sorry for Brexit” moment, in which the UK would make substantial concessions to build out a skeleton trade arrangement into stronger ties? Is this going to be the result of what the Chancellor Rachel Reeves in a vague promise this weekend calls a “step towards closer partnership in further areas”?

Or is it essentially more like a balancing act, in which the UK gets the best of both worlds from closer ties with the US and another deal with India? Buccaneer Britain striking different arrangements where it can, and telling both sides that it agrees with whoever is in the room that day?

Starmer is happiest with ambiguity, which sometimes plays out OK: he has at least secured respite from the bludgeon of the Trump tariff splurge, as the EU seeks to align responses in confusion and ire. The risk is that the Government’s big picture can appear inchoate – as many insiders have recently been warning or venting.

Tomorrow is the moment that will clear up some of Keir’s Great Europe mystery. Not without some drama – Starmer held last-minute talks with the EU Commission President Ursula von der Leyen and French President Emmanuel Macron to iron out sticking points in the shape of a proposed mobility scheme to allow a visa for (relatively) youthful people to live and work in the UK and EU reciprocally. There was also the hardy perennial of arguing with France about fishing quotas.

Prediction: some sort of deal will get across the line tomorrow – and a lot of people will be disappointed by the outcome. Are Remainer “reconnectors”, who harbour the diehard hope that the Starmer project means that barriers to connecting with Europe disappear, going to be impressed by the scope of the youth mobility scheme and the numbers of to-and-fro-ers it allows, or find it the stuff of reconnection dreams? Especially those who, like this columnist, feel aggrieved to be pushed into the queue of doom: “other countries” lines to enter the EU – while their Euro colleagues sail though without the palaver.

I sense No10 will not want to make this a centrepiece, when its focus is on voters in areas where Reform is at its heels – rather than the places where there is a bigger take-up of young people hankering to work as baristas in Berlin or on start-ups in Lisbon.

It does not take a modern Klemens von Metternich (the father of modern diplomacy), combined with an Otto von Bismarck (uniter of political and territorial difference in his 19th-century vision of Europe) to see that Starmer would be dead meat if he agreed to the full “reconnection” menu. His home front is in a politically perilous state – and even supportive souls wonder how the combination of swingeing disability welfare cuts and a wobbly growth agenda will cohere into an electorally persuasive vision.

Anyone inclined to believe the comforting story that the UK would at heart “really” like to undo Brexit and rejoin the EU clearly has not been watching the message from the parts of the country increasingly attracted to Reform closely enough. There is a mighty difference between people thinking politicians mishandled Brexit and voters thinking they made the wrong decision themselves.

So Starmer cannot simply indulge the urban-liberal ”Rejoin” tendency too much. He needs to show that the UK benefits in unambiguous ways from this rapprochement, and that will be the standard on which this summit is ultimately judged. No 10 is keen to convey that the outcome is intended to benefit those “working people and their families” – but the simple question “how?” will still loom large.

Similarly, Starmer needs to show progress for the small- to medium-sized businesses most affected by added trade frictions since 2016. The Chancellor will host a business breakfast and reception jointly with No 10 to signal that the re-connect is intended as a “first step”, but struggling companies will say they need more – and faster than tomorrow.

The easiest area for a UK “win” is on defence. The UK took a leading role in supporting Ukraine when others wavered after the invasion in 2022, has an army with combat experience and an arms industry as a core ally. Proof of this would be an agreement that Britain can bid into the massive new €150bn defence fund. The risk is that the UK does its bit – and still ends up on what one senior defence official calls the “never-never” list.

Inevitably, 11th hour trade-offs beckon – which are not especially logical but reflect the pragmatic challenges for a single country outside the EU, dealing with a mighty trade bloc across the channel. A new agreement on agrifoods would hearten farmers and benefit consumers, but with much trouble for Starmer if that were to end up pulling Britain back into the era of “dynamic alignment” with EU food standards – in essence, the opposite of the “take back control” message he has tried to wedge into Labour politics.

Ditto, I can’t see anything getting across the line which has a role for the European Court of Justice here – at the time Starmer’s “control” message means moving UK immigration and asylum policy decisively away from the remit of the court.

Yet one thing will have been achieved tomorrow to Starmer’s credit – the sense that the UK has rejoined Europe’s “family and friends” scheme and that the default tone of mutual testiness in the scrappy aftermath of Brexit has been ditched. We are back on speed-dial terms with Europe’s leaders. 

The result will be a down payment on a closer relationship – and that is good news. On the way lie many hurdles. The biggest will be Starmer’s ability to tell sceptical voters, whatever they voted in 2016, what is really in it for them.

Anne McElvoy is executive editor of Politico and host of the Politics at Sam and Anne’s podcast with Sky News