It is said that all political careers end in failure.

But Alex Salmond, who has spent his political life defying lazy or patronising assumptions, especially those of complacent Westminster politicians, has proved otherwise, despite Yes Scotland losing the independence referendum.

Thursday did not to mark the brave new dawn of an independent Scotland. The result was decisively in favour of Scotland remaining part of the UK.

Yet the choice of 1.6 million out of Scotland's 4.3 million registered voters to back independence is by any standard an astonishing endorsement of this one man and his achievements. Such a result would probably have been inconceivable in the hands of any other leader. It was made still more extraordinary by the pro-independence vote in Scotland's largest city, once an impregnable Labour fortress, along with the city of Dundee and the Labour heartland of North Lanarkshire. Democracy thrives when long-standing one-party dominance is threatened and challenging that, too, is an accomplishment on Mr Salmond's part.

Fifty years ago, the Scottish National Party was regarded as the preserve of eccentrics and even extremists; 30 years ago, it had yet to mature into a credible election-winning force. Today, it is one of the most effective, professional, progressive centre-left parties in western Europe with a highly defensible record in government. There is little in the way of failure to discern in that.

That the constitutional settlement of the whole United Kingdom is now in flux; that the referendum registered the highest turnout at any British poll since women under 30 got the vote in 1928; and that Scotland has reached a point "redolent with possibility" - the possibility of greatly enhanced powers for its parliament - stands as his legacy. The repercussions of this week's momentous vote will be felt for years, if not generations, to come.

Or at least they will so long as the politicians in whose hands the future course of Scottish devolution now rests deliver on their fraught pre-poll promises. During his dignified resignation speech yesterday, Mr Salmond noted with a hint of weariness but little discernible surprise that the Prime Minister had already backtracked on Gordon Brown's promise of a second reading vote on further devolution by March 27 (meaning that the draft legislation would have little chance of making it onto the statute book before Parliament is dissolved for the election). He declared that the Labour-Conservative common front on the issue had already crumbled.

This matters very much. It will only fuel the fears of those voters, on both sides, who doubt the UK parties' will to agree and enact a meaningful programme for far-reaching further devolution swiftly, now that the immediate threat of Scottish independence has receded.

Already yesterday, Labour and the Conservatives were circling one another over the role of Scottish MPs at Westminster. Mr Cameron's pledge to ensure that only English MPs vote on English issues would put right a long-standing unfairness, but has the not inconsiderable benefit to the Conservative Party of making it more difficult for a future Labour Government to maintain influence over English domestic affairs, as well as diminishing Labour's influence at Westminster generally. Labour leader Ed Miliband responded archly to Mr Cameron's statement by declaring that he would resist any attempt by the Tories to exploit the situation for "narrow political advantage". If he is serious, then that guiding principle must apply more broadly. Of the three UK parties, Labour have offered the most anaemic vision of greater devolution, fearing the impact on the relevance of its Scottish MPs. Party political manoeuvring, however, cannot be allowed to shape the proposals. This newspaper has warned repeatedly that if the three UK parties break the promises they made to Scottish voters in the tripartite "vow" of last week, pledging to ensure "extensive new powers" delivered within an agreed timetable, then the electoral implications will be very serious indeed.

They must deliver. If they do not, then the clamour will grow for another referendum. If Labour are worried about the diminishing relevance of their Scottish MPs now, they must carefully consider how they would like to see them lost altogether. That could happen as soon as next year's General Election if they are seen to be putting party political interests before Scotland's demands.

Nor should politicians either north or south of the Border be permitted to dominate this debate, after a campaign that has seen such a remarkable level of public engagement. As Mr Salmond put it, "the real guardians of Scotland" are the tens of thousands of Scots engaged in the political process. Scottish civic society and individual Scottish voters must be afforded the space and time to make their voices heard. Lord Smith of Kelvin, the crossbench peer who has been asked by the UK Government to oversee the development of cross-party proposals for greater devolution, has pledged to reach out to them, noting that the millions involved in the referendum are not all represented by political parties, or even by institutions such as trade unions or interest groups, but are individuals whose voices must be heard. Achieving that within the tight timetable the three main UK parties have set for themselves will not be easy, but the involvement of individual Scots in this process could not be more important for its very legitimacy.

The Herald will not sit by and watch the process of devolving more powers lose momentum or become subject to the self-interested horse-trading of the Westminster political establishment.

The three UK party leaders and their colleagues received the fright of their political lives earlier this month when they thought they might be about to preside over the break-up of the UK. They had foolishly underestimated Mr Salmond, but they had also perhaps imagined that the Scottish voting public would be more biddable, more easily appeased. They have learned otherwise, and it is a lesson they allow themselves to forget at their own risk. They will find that voters will not be fobbed off - not only voters in Scotland, but in the other nations and regions of the UK where a similar passion for change has been aroused.

Mr Salmond said earlier this week that there would not be another independence referendum for a generation. This is common sense: the people of Scotland would mostly be wearied by the thought of another contest, even many Yes activists. But voters desire a fundamental shift of power from Westminster to Scotland. If they do not get it, a fresh referendum could take place sooner than anticipated.

After fighting the campaign of his life, Alex Salmond has stated his belief that "Scotland can still emerge as the real winner" from the referendum contest. Now it is the turn of the UK parties to rise to the occasion.