Whatever the outcome of the EU referendum, the future of UK politics looks more uncertain than at any time in living memory.
The Conservative Party is irreparably split. The bitterness of the campaign has been astonishing. The fault lines in personal relationships across the party are deep and, I suspect, unbridgeable.
It is hard to see the Prime Minister staying in office for long. But although we have become used to the notion of a Johnson/Osborne/May fight to be the next occupant of No 10, could any of this troika reunite the Party? I think not. Eurosceptic Conservatives have much in common with UKIP, and could command a healthy vote in any election - possibly around 25%.
But we have seen a resurgence of what we sued to call "One Nation" Toryism, - those such as Sarah Woolaston and Baroness Warsi who have publically rejected the acerbic traits of colleges. The impressive performance of Ruth Davidson - both in the Scottish elections and the EU campaign could be the catalyst for a move back to the centre, which would itself have a strong electoral pull.
So we have the real prospect of a staunchly right wing Conservative/UKIP block, and a reasserted One Nation grouping. But as we look to the left of the political spectrum we see challenges there too.
Jeremy Corbyn is firmly in control of the Party machinery. Labour's share in recent elections is generally improving. But the party's message is struggling to be heard and its core vote is vulnerable, outside of the South East particularly, to UKIP. The party's collapse in Scotland and redrawn Westminster constituency boundaries make it much harder for the Party to win a majority.
In this scenario, for both a fractured conservative party and a constrained Labour one, constitutional reform makes increasing sense. Would not a "leave" result would create an unstoppable momentum for Scottish independence and may even loosen English-Welsh ties? London will surely vote Remain, and is becoming ever more distinctive to other parts of the UK. But the devolution of powers away from central government (the so-called "Devo Manc" model) has been enthusiastically embraced - not least by Labour who see it as an opportunity to address the imbalance of political forces at Westminster.
The level and spread of regional autonomy in the UK could soon cross the Rubicon. So the question must be how to ensure that the exercise of devolved power is by directly elected representatives who reflect the political views of the population. A new constitutional settlement, especially one in which old political power blocs have changed, could make proportional representation not only desirable but necessary.
The future is of course unwritten. The post-referendum landscape will inevitably be different, and we can't leave it to others to shape it. The opportunity to shape a new constitutional settlement - that takes the heat from the referendum campaign and produces something effective, enduring and empowering - is one we must take.