Even in cases where U.K. participation has been agreed as fine in principle, it can sometimes be blocked in practice by making difficult-to-meet demands of London: usually financial.

A plan for the U.K. to join the first phase of the EU’s SAFE rearmament loan scheme was entirely scuppered by an insistence that London pay billions of euros to participate. Talks ended without agreement by mutual consent.

Running out of road

There may also be trouble already on other files.

Already, EU capitals have attached new conditions to the electricity trading deal conceived at last year’s summit, setting a new requirement that Britain pay into EU “cohesion” funds in exchange for access. Whether the two sides can agree a number remains to be seen.

For these reasons, some observers are skeptical Starmer’s pick ‘n’ mix approach can be taken much further.

“We’re kind of running out of the approach of ‘what more could we get through little bits of single market access,’” David Henig, U.K. director of the European Centre for International Political Economy (ECIPE), told a seminar at the University of Sussex earlier this month.

“In order for the U.K. to substantively move on beyond the current negotiating agenda, it will need to make a much bigger leap, rub out some of those red lines, and start being prepared to talk about substantial financial contributions, movement of people, and more generally, about being partners with Europe,” Henig added.