So what happens now?

Scotland took itself by surprise on Thursday. No one expected such a decisive affirmation of national autonomy by the Scottish voters, least of all the Scottish National Party.

It was as near a clean sweep as makes no difference - 56 out of 59 MPs. But what happens after the opposition parties are effectively wiped out in the most dramatic political realignment in Scottish electoral history?

Well the first thing that happens is that everyone keeps calm. This is not a Unilateral Declaration of Independence. "The Scottish lion" is not "roaring" at nameless adversaries, as Alex Salmond suggested on election night. Scotland does not need a rush of blood to the head.

Nicola Sturgeon has avoided triumphalism and intemperate language in the wake of this result as she had during the campaign. This to be welcomed. It is a sign of strength not weakness. There will be plenty of provocations to come; plenty of time for righteous indignation and ringing declarations of intent.

There remains a sense of bewildered hurt in unreconciled sections of the UK media and in the unionist parties. The Conservatives played a very dangerous game during the election by appealing to the worst anti-Scottish sentiments in the UK electorate.

That poster of Alex Salmond in a black turtle-neck picking the wallet out of an English voter's back pocket will remain the abiding image of the 2015 general election campaign.

If anyone is in any doubt about its impact they should view the Guardian journalist, John Harris's, excellent report from the English marginal constituency of Nuneaton. Scots he concluded have become bracketed with benefits scroungers and immigrants as undesirables.

But it is important to remember that this is not England. It is a crude distortion projected though the mirror of a malign UK press and a Conservative party that has lost any sense of what it means to be "one nation".

The vast majority of English people hold no animosity towards their neighbours north of the border. Scotland's politicians must avoid any rhetorical retaliation for the Tory campaign that could be interpreted as evidence of anti-English sentiment by the UK media.

Back home, the claims that Scotland has succumbed to a "personality cult" as the former Labour MP Michael Connarty put it only confirmed the extent to which the Labour Party has failed to comprehend the nature of its defeat.

No doubt sections of the Scottish media will continue to claim that Scotland has "gone mad". That voters have been seduced by a 'far right' ideology. This will only further erode those commentators' threadbare credibility.

The transformation in the landscape of Scottish politics has been revolutionary. But it has been conducted in an entirely democratic and lawful manner, despite repeated attempts to suggest otherwise.

There was not a single arrest, not a single punch thrown, not a pane of glass broken. The only egg was hurled at the Prime Minister by Labour supporters in Bath. Rarely in world history has a question of national sovereignty been addressed so peacefully.

Now is the moment for all sections of the Scottish media and the political class to abandon crude stereotypes. The partisan attack journalism that has infected coverage of Scottish politics in the last three years. This has led to a breach of trust between voters and the fourth estate.

Half of Scotland has simply stopped believing anything they read in the papers, even when it is true. This is not healthy. The media and SNP voters need to mend fences. The press must return to the job it is there to do: which is to hold government to account not issue propaganda.

Now that the Scottish National Party dominates both in Holyrood and in Westminster elections this scrutiny role is going to be more important than ever. No matter how moderate and democratic their leaders may appear, all political parties succumb to the arrogance of power.

When leaders have obliterated their rivals they also risk obliterating their sense of proportion and start believing they are infallible. The SNP needs to bear in mind that 50% of voters did not vote for them last week.

And that all governments make mistakes - like the attempt to abolish the requirement of corroboration in criminal trials. Fortunately, Nicola Sturgeon appears to be aware of her government's limitations. But the First Minister risks being surrounded not by a diverse democracy but a fan club.

Also, in this new and demanding era of Scottish democracy, it must be clear that she is the leader of the party in Westminster as well as Scotland. There will be great challenges and controversies ahead.

The Scottish National Party will be the third largest party in the House of Commons, by a considerable margin now that the Liberal Democrats have been largely destroyed.

This will transform SNP party finances as it receives parliamentary Short money and salaries. The SNP will also have representation in debates and on parliamentary committees. It must use its influence constructively.

But the 56 SNP MPs will have very little formal power in a legislature of 650. They face a Conservative party under David Cameron intoxicated by its unexpected success and its liberation from the moderating influence of its former Liberal Democrat coalition partners. This could cause frustration.

Cameron is determined to push through what looks like the most radical and divisive right wing agenda seen in Britain since the days of Margaret Thatcher in the 1980s.

This includes a further £30bn in public spending constraints including a £12 billion attack on the already squeezed living standards of people living on welfare.

The benefits cap is to be tightened. Universal credit will be fast tracked. Measures like the bedroom tax will be enforced and young people deprived of housing benefit. These will apply also in Scotland because welfare is not devolved.

There may be further cuts we cannot yet envisage. The Tories have sought to bind their hands by legislating to make increases in income tax, VAT and National Insurance illegal. This is fiscal madness.

The 56 Scottish National Party MPs will oppose these measures vigorously but they must realise their limitations. Already one can hear the claim that they are - like Labour in the 90s - the "feeble fifty six". But they should not avoid crude protest politics and disruption.

Trident will be renewed and continue to be located on the Clyde despite the opposition of 95% of Scotland's members of parliament - including the sole Labour MP Ian Murray.

There will be very little the SNP parliamentary group can do about this. However, it will still carry a strong moral voice in Westminster and it must use it.

The UK Labour Party appears to be descending into a period of introspection following its defeat. It has lost confidence in the moderate social democratic agenda promoted by its former leader, Ed Miliband.

Many on the right of the party seek a return to the days of Tony Blair and New Labour. This means that the SNP may find itself the most articulate voice of left of centre values in the UK. It is a role that Nicola Sturgeon has already played during the general election campaign.

The Nationalists should have no hesitation in presenting themselves as the liberal conscience of the House of Commons. They should condemn attacks on immigrants and welfare recipients and prevent Westminster succumbing to xenophobic populism.

Nicola Sturgeon insisted that the general election was not about independence. But the constitution will never be far from the agenda of the 56. The first crisis will arrive in 2017 when David Cameron delivers on his promise of an In Out referendum on British membership of the European Union.

Nicola Sturgeon has warned that there will be a crisis of legitimacy if Scotland is forced to leave the EU on the strength of UK votes. She says this should be a decision for "the family of nations" in the UK and not Westminster alone. This is not likely to find favour with voters south of the border.

Nicola Sturgeon has also suggested that the EU referendum may present precisely that "change in material circumstances" that could trigger another independence referendum. It is most unlikely, however, that David Cameron would authorise another independence referendum so soon after the last one.

Nor is it at all clear that Scots would vote any differently than in September 2014 - especially if the referendum was not sanctioned by Westminster. Sturgeon may have to take care that her rhetoric does not raise unrealistic expectations amongst her legion of enthusiastic followers that an early referendum can or should be held.

However, the 56 SNP MPs must use the debate on Europe as a means of asserting Scotland's right to a say in what will be the most important constitutional issue facing Britain in the next five years. Nicola Sturgeon should try to mobilise support from the Welsh parliament and from Northern Ireland politicians for a triple lock on the question of EU membership.

Before that, there will be more immediate constitutional issues for the SNP to address. The First Minister has called on David Cameron to listen to Scottish votes and accept further constitutional reforms beyond those offered by the Smith Commission. Smith, like the Vow that inspired it, is clearly past its sell by date.

There are rumours in Westminster that Cameron is considering a 'big offer' to the Scots, perhaps even something approaching full fiscal autonomy. Some Conservatives MPs are thought to favour this approach on the grounds that it would give the SNP 'enough rope to hang itself'. The collapse of oil prices has made the economics of FFA seem precarious.

It seems most unlikely that the PM will introduce full fiscal autonomy because he has argued consistently against it in the past. He has always said that FFA might make Scotland effectively an independent country, and Cameron does not want to be the prime minister who presides over the break up of Britain.

Instead he intends to press ahead with plans to devolve income tax powers to Scotland and reduce the role of the Barnett Formula in determining Scottish public spending increases. This will have to involve Scottish MPs. They will need to use their influence on parliament's committees to ensure that Scotland does not lose out in this process.

Cameron has also made clear that he intends to press ahead with English Votes for English Laws (EVEL) to address the West Lothian Question. He says that it is unfair for Scottish MPs to have a vote on English bills when English MPs have no such say on legislation in Holyrood.

The Conservatives now have that all-important majority in the Commons that would allow them to pass EVEL into law. This would effectively lock Scottish MPs out of important votes on legislation, for example on the English NHS, that could have direct consequences for Scotland.

The SNP MPs will vigorously oppose this but may not be able to prevent it. But no one should be in any doubt: EVEL within an unreformed unitary Westminster parliament will simply turn Scottish MPs into second class citizens.

The moral case for an English parliament is, of course, unassailable if England wishes to have one. However, this would require a federal reconstruction of the UK constitution, with a directly elected Senate in place of the House of Lords and English devolution. There is little evidence that there is the political will in Westminster for such an exhaustive process of reform.

It may well be that this conjunction of circumstances - the Scottish landslide, the EU referendum, English Votes for English Laws - will generate an unstoppable momentum that will lead Scotland out of the United Kingdom.

History seems to be speeding up. The elimination of the unionist parties in the general election and the establishment of a right wing Tory government may be the perfect storm for the UK. By 2020, Scotland may already be on the way to independence.

However, it is important that Scotland's renegotiation of its place within the UK does not lead to economic dislocation and social disruption. The welfare of Scotland's citizens must be the primary concern of Scotland's MPs at all times, not nationalist ego-gratification and political grandstanding

The constitutional journey that Scotland embarked upon back in the 1980s with the Scottish Constitutional Convention has been a consensual and measured one involving all of Scotland's citizens. Much has been achieved without confrontation and needless division. Long may this continue.