As a country, we are facing our biggest challenge and shake-up to society since the Second World War.
As we look around, we see divisions and inequalities that are already damaging our way of life. But we also see grounds for hope and the capacity to overcome our problems.
Brexit makes the future more uncertain. We must heal the divisions caused by the vote and accept the dissenting voice as well as the majority. Those who disagree with us are not our enemies.
I’m not Eeyorish about our prospects post-Brexit, but neither am I blandly optimistic that we are destined for the sunlit uplands.
The reality is that over the past few decades – under governments from across the political spectrum, and driven by forces beyond the powers of any one party – the most important building blocks of our nation have been undermined.
Take housing. We must build proper homes – and have a housing policy that is about creating communities, not just bricks and mortar.
The ugly disparity between the mansions that some can afford and the poor housing that others must inhabit shows how badly our society has been corroded.
The tragedy of Grenfell Tower, a metaphor for our collective failings, shows us that we need a moral revolution in housing that centres on people.
There are inequalities in our healthcare system as well. The NHS lacks coherence and a sense of the values it was founded on. Many of our elderly are neglected and lonely. Too many with mental health problems are ignored.
All must receive medical care free at the point of delivery. To deny this is an attack on the common good, on the solidarity of our society. Every person must also receive high-quality care, because every person is equal before God, and all are made in the image of God.
In economics we welcome growth and disciplined and properly behaving markets. Equally, human dignity demands that economics is made for people, not people for economics. Unfettered greed is not merely distasteful, it can wreck lives and whole economies, as we have seen.
Jesus spoke of God’s love for the poor, and of woes for the wealthy and complacent. We are a country that can meet our needs and be generous on top to the rest of the world. To have a vision to do both reflects Britain at its best.
Welcoming strangers to our country and integrating them into our culture is important. We must be generous and allow ourselves to change with the newcomers and create a deeper, richer way of life. We also need to support strongly those poorer communities that have had high levels of immigration.
We also need a foreign policy that engages with areas of suffering so they become places where humans flourish, not where they flee from.
There have been profound shifts in our understanding of the family. It must be at the heart of our society and needs strong support for all those who seek to build stable, faithful and lifelong commitments.
The discussions about what is best and right in family life will continue, but they must be based in the certainty that every human being is made in the image of God and must be valued with dignity.
And we cannot thrive while education is marked by cuts and inequalities. It threatens our togetherness. Without a properly funded education system with values at its core, our long-term outlook is poor. This applies not only to the highest performing child but for all.
Brexit has divided the country and we now need a new narrative, one that is rooted in all that is best in our history – solidarity, courage, aspiration, resilience and care for each other. There is a danger that there is a schism in our society into which the most vulnerable are falling. Austerity is crushing the weak, the sick and many others.
With our history and heritage of ethics we have every reason for hope. We have reimagined ourselves before, after 1945 for example, across all parties, and inspired by Christians such as historian R. H. Tawney, Archbishop William Temple and William Beveridge.
That reimagining, based on Christian values and led by believers and non-believers alike, led to great institutions such as the NHS.
Today in Britain we are suffering from a lack of such common values – values that have deep roots in our nation’s Christian history.
There will be great changes regardless of whether they are based on those Christian values or whether we just let things take their course.
But if it is the latter, then the consequences for the poor and needy will be dire, our pride in our country diminished and our contribution to the world stifled. We must use hope to heal for the future. We must be a warm, welcoming nation. We must never crush the new diversity and freedoms.
It is the duty of the Church and of all us to reimagine what it means to be this remarkable nation in the 21st Century.
Justin Welby’s new book, Reimagining Britain, is published by Bloomsbury on March 8