Even for a general election that everyone said was the most unpredictable for several generations, the result is extraordinary.

If the exit polls are correct, the Tories have done much better than expected, the SNP have delivered a stunning result that even they did not expect and, for the first time in their history, won a general election in Scotland, and Labour faces the extraordinary prospect of wipeout in the nation it once took for granted as its political homeland.

And the big question is: what happens next, now that great cracks have appeared in the British political landscape? Before polling day, all the talk was of the legitimacy of a minority Labour administration, supported by the SNP. Commentators were asking: could such a Lab/SNP arrangement work when the Conservatives were the biggest party?

However, last night's results have turned that question on its head. Instead of discussing the legitimacy of a minority Labour government (and under these figures, even with SNP support, Ed Miliband would be way short of the winning line) instead the question of legitimacy is faced by David Cameron and the Tories, potentially supported by the Liberal Democrats and the DUP. If these parties seek to form a government for the whole of the UK, how legitimate can it be when it has not a single MP in Scotland? Should Mr Cameron drive the process forward in the next few days and claim victory, questions over the constitution will never be far away.

The SNP must be cautious in its response though. The party has pulled off a stunning result, powered largely by the momentum built up by the referendum last year, but half of Scotland did not vote for the SNP and the party holds virtually all Scotland's seats because of the outdated vagaries of the first past the post system. Before the election, senior SNP sources said they would support a single transferable vote system and they should now be true to their word because the first past the post system is broken beyond repair. The seats won by UKIP and the Greens do not reflect in any way the number of votes they won but the fact that a party can take around half the vote in Scotland and win the vast majority of seats is evidence of a dysfunctional, unfair system in immediate need of reform.

Of course the Tories may not think so after their results. In the last few days, Boris Johnson said he would be up for talks about a new political system and a federal structure for the UK, but the Conservatives may be tempted to think now that everything can go back to normal. They are wrong. The Tories are the biggest party, but they are short of a majority, which reflects the fragmented nature of political support. It is the new reality and every party must adjust to it.

The consequences of the Conservatives ignoring that are profound, and should they form the next government, they should engage in serious, mature, progressive talks with the SNP and other parties about how the electoral system can be made to work for the whole of the UK. This year's campaign was less than inspiring and the lesson for the parties must surely be that if anyone is ever going to build a truly broad, national momentum, it will not be from behind the high walls of party HQs. They have to get out there and speak to the people.

Over the next few days, it is each other that the politicians will be speaking to as they try to form an administration. However, they should remember this: no one has truly won this election, but there is still a victory within reach: a better, fairer, more consensual way of running the country.