Nicola Sturgeon’s resignation as First Minister of Scotland comes at a critical moment for the Union, since the question of Scottish independence has inevitably been tied to the ongoing dilemmas over Brexit. It seems that, over the next week or two, the UK and the EU will announce a potential agreement over the revision of the Northern Ireland Protocol. Goods travelling from mainland Britain for consumption in Northern Ireland will no longer be subject to automatic checks; a trusted trader scheme will allow most shipments to be waved through. In return, it appears that the UK government has dropped its opposition to the role of the European Court of Justice as the ultimate arbiter in disputes involving trade between Britain and the island of Ireland.

It is not guaranteed to succeed: the DUP is said still to be resisting. Without its support, government at Stormont cannot be restored and Northern Ireland will remain in democratic limbo. But it is a positive development that progress has finally been made on this open sore and resolving this matter will go a long way to negating the idea, often touted in Scotland, that Britain’s departure from the EU is bound to lead to a break-up of the United Kingdom not just across the Irish sea but to the north, too.

The UK parliament should never have agreed to place an internal UK border down the Irish Sea. That it happened was in part due to the ennui generated by several years of Brexit negotiations: Conservative MPs were so desperate to get Brexit out of the way that they failed to spot the toxic ingredient in Boris Johnson’s ‘oven-ready’ deal.

That said, there are some who favour the arrangement whereby Northern Ireland remains within the EU single market for goods, and see it as a means of attracting investment to the province. Whatever the merits of placing Northern Ireland in a unique situation, a settlement of the current problems will be welcome, and not just in that it will make life better for business. It also might signal the end of the bitter phase of relations between Britain and the EU, whereby from now on, we will be able to have more constructive negotiations on matters of mutual interest. This might be more likely now that the main protagonists of the Brexit negotiations – Johnson, Jean-Claude Juncker and Michel Barnier – are no longer centre-stage. It might become even easier once Emmanuel Macron has left office, too.

It is not enough, however, simply to seek better relations with the EU: politicians must seek agreement at home. That was the laudable aim of a mini-conference last week at Ditchley Park attended by Peter Mandelson and David Lammy on the one hand and Michael Gove and Gisela Stuart on the other. But if Brexit is ever going to be worth the trouble it has caused we are going to have to look beyond that. The point of Brexit was to turn Britain into something other than a European-model social democracy, such as a more open, more freely trading, more business-friendly opportunity economy. But if all we want is to remain as a Belgium or a Sweden, we would be better off inside the EU.

As things stand, Rishi Sunak’s government is doing little if anything to justify Brexit. The tax burden has increased markedly since we left the EU and regulation has hardly been touched. We have replicated the trade deals we had as members of the EU but made little progress beyond that, other than with Australia. Britain’s application to join the Trans-Pacific Partnership is an imaginative way to plug the UK economy into a more dynamic region of the world, but that may take time to come to fruition.

Wanting to be friends with the EU is good, but we have to appreciate that we are competitors, too. Taking business from the EU is the process by which we can turn Brexit from a source of national anguish into a positive step. But we are not doing well so far. True, Britain has attracted plenty of investment since Brexit, including some from companies who were predicted to leave our shores. On the other hand, AstraZeneca’s decision to build a new factory in Dublin rather than Cheshire is an embarrassment. The company’s CEO, Pascal Soriot, was quite open about why he had made the choice: Ireland has a more favourable tax regime. In Britain, on the other hand, corporation tax is due to rise from 19 per cent to 25 per cent, and tax incentives to invest are being watered down. The UK government needs to put that right, as well as to investigate other ways of promoting life sciences, which were supposed to be one of the big beneficiaries of Brexit. At present, it takes too long for pharmaceutical companies to progress from applications for clinical trials to administering the first drugs to patients – an average of 247 days compared with 155 in the US.

Brexit was always going to be a slow-burn: while the disadvantages would become immediately obvious, the opportunities would take time to seize. But the government will have to make headway with exploiting Britain’s newfound freedoms – or risk a steady growth in the number of people who wish we had never left the EU. The obstacles to a successful Brexit are many, but with Sturgeon’s resignation and the possibility of progress on the Protocol, Sunak may have a chance now to cast himself as the prime minister who saved the Union. That would be no small feat.