Denial, despair and drift are not an option. We must now get back to work.

More than three months on, many Brits remain shocked at the referendum result. Some are still grieving. Some are even giving up. I think that the Brexit vote had a more profound impact on our collective psyche than anyone anticipated, an impact that will endure beyond the extraordinary weeks of political change it triggered.

But denial, despair and drift are not an option. We must now get back to work.

The defining moment for the UK's place in the 21st century is not the referendum itself, but how we respond to it. The period ahead will require a sense of collective purpose that we have not demonstrated since the Second World War. We must marshal our best instincts, and not our worst. We need to stop the defeatist and declinist talk that is using up so much oxygen - the world is listening. And rebuild a sense of a shared national project. Politically, this means it is time for the biggest tent possible. I hope that we can focus more on four priorities.

Firstly, confronting racism and hate crimes - that is not the Britain we know. We all need to speak out more strongly for the vital British values of tolerance and diversity. The right to be racist was not on the ballot paper in June. We cannot let the English hooligan come to define how the world sees us.

Secondly, reassurance to our international partners and investors. Business leaders from both sides of the debate should set out how UK business can retain our role as a major trading nation. I'm sure that the UK's ambassadors have had instructions to get out on local TV (in the local language), explaining that we remain as open to the world as ever. And that we'll see ministers despatched to every continent to hammer home the message on Britain's outward looking offer to the world, based on our history as a great trading nation; our global reach; and our strengths as a financial centre and creative industries superpower.

Thirdly, sober and careful negotiations for a dignified exit from the EU. The government has a crack team of civil servants on the case. The appointment of Oliver Robbins to lead at the London effort is reassuring to everyone who knows the work rate and talent he brings to the project. And having Sir Julian King as the new Commissioner in Brussels gives the UK the best possible reach, expertise and influence within the EU system.

Fourthly, shoring up the Northern Ireland settlement. This is urgent. The last two decades have seen painstaking, courageous and visionary work to redefine the challenge in a way that can give hope to future generations. But this is a young peace settlement, and fragile. Many are looking for the opportunity to make it fail. We need a determined effort to think through the implications of Brexit.

We should also learn the lessons of the referendum. The next period must be an opportunity for Britain to consolidate its strengths as a 21st-century powerhouse based on liberty, tolerance and creativity. We need to develop a more positive and honest political debate, finding ways to put more power in the hands of citizens, and reinvigorating public life with fresh ideas. There is huge anger from those who feel that they have been left behind by globalisation.

We need to have a new conversation on migration, which helps us benefit from our openness and diversity, but ensures that plans are in place for essential services to keep up. And to make genuine efforts to reduce the inequality that will otherwise breed more extremism.

The key now is to pull together to ensure that negative predictions about leaving the EU are proved wrong. We have to take on growing cynicism, division, fear and rancour. In the creative industries, for example, there is a willingness to identify the opportunities offered by Brexit, even though the sector was overwhelmingly in favour of remain. Downtown Abbey, Adele and Sherlock could help us get our mojo back.

But there are major challenges. Much of the success of the arts and creative sector, the fastest growing part of the economy since the crash of 2008, has been built on freedom of movement of talent and easy cultural exchange. So there are concerns about the retention and recruitment of staff needed to maintain that vibrancy. It is also a sector that needs proper protection of intellectual property rights.

The answer to the 21st century is not a bigger wall, so let's not mistake 23 June as a vote for isolationism. But seize it with confidence as a moment for national renewal, and rebuild together.

Illustration by Andy Watt.

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