Dr Paul Flenley is the subject leader in politics and international relations at the University of Portsmouth. Here is what he has to say after Brexit.
We are at a major turning point in British history. With the loss of empire the UK had looked for a new role and identity. It found it in closer co-operation with its European neighbours.
As one of the big three in Europe the UK was able to play a leading role not only in the EU but internationally as a bridge between Europe and the United States.
The decision to leave the EU radically changes all this.
It is not clear what, if any, the UK’s role in the world will now be.
Yes, we remain a key member of Nato but our military capability has now significantly declined and is dwarfed by that of the United States. The question of our identity is now back on the agenda.
In the 1970s we had been ‘the sick man of Europe’.
From the 1980s onwards the UK within the EU had made a success of the single market, which it had promoted, and turned itself into the fifth largest economy in the world.
The implications now for the UK economy are uncertain. It will take time to negotiate a new deal with the EU which will still remain our major trading partner.
In addition we will have to negotiate new bilateral trade deals with all those non-EU countries with which we trade as part of the EU.
Such deals cannot risk conflicting with those signed with the EU.
Investors will want to hedge their bets and not commit themselves to significant investment in the UK until the details of the future relations between the UK and the EU have become clear.
Paradoxically, the complexity of exiting and re-establishing our relationship with the EU will mean that for the next few years the EU will consume more of our attention in practice than ever before.
The referendum could also challenge the make-up of the UK itself. Depending on any new deal between the EU and the UK, the Scots may want to revisit the issue of Scottish independence.
Northern Ireland may not want to see the border with the south once more become a major dividing line – this time between the EU and the UK.
The referendum also reveals deep divisions within England itself. London is now very different from the rest of the country.
There is a generational divide between the interests and vision of the under-25s who largely voted to remain in the EU and those of the older generation.
The referendum also exposes the frustrations of those who have felt ignored by the political class.
This is a phenomenon not only in the UK but also the rest of Europe and in the US in the form of support for Donald Trump.
The Labour Party seems to have lost touch not only with its ‘natural’ supporters in Scotland but also now in the north of England, who voted to leave.
For the Conservative Party Europe has long been the key source of division. By offering a referendum David Cameron had hoped to buy off the Eurosceptics and solve the issue once and for all. Instead it has handed power to them.
Just over a year after his unexpected electoral victory the referendum has not only ended his premiership but perhaps the defeat of his project of a more liberal compassionate conservatism.
In short, nothing will ever be the same again.