Of all the rhetoric produced by the referendum, the notion that the UK was somehow "broken" irritated me the most.

Critics of a particular system of government naturally exaggerate its weaknesses in order to make their suggested alternative seem all the more compelling, but some of the language deployed was hyperbolic.

The academic Tom Nairn must be partly to blame, for it was his 1977 book The Break-Up of Britain which, in attempting to reconcile Marxism with nationalism, used words such as "ramshackle" to describe the UK.

And listening to some supporters of independence during the last couple of years you could be forgiven for thinking the UK had become what's known in international parlance as a "Failed State".

Well I spent this weekend past in a Failed State, and I can authoritatively report that the UK does not fall under that category. The Caribbean republic of Haiti, however, does.

A drive around the earthquake-scarred centre of Port-au-Prince puts everything into perspective. Infrastructure was bad before the 2010 quake and even worse now; the poverty is pervasive, the filth unmentionable and the prospects of anything improving remote.

I write none of this with the intention of belittling the genuine poverty and inequality that exists in the UK, but I am making a plea to put matters into some perspective. Haiti can justifiably be described as "broken"; Britain or the UK cannot. In fact, by most standard measurements it is one of the least broken.

But the adjective falls all too easily from the lips of critics who long ago reached their conclusion and now work backwards, grasping zealously at the means with which they can justify the end. Writing on the Common Space website, for example, the lecturer James McEnaney recently cited Messrs Straw and Rikfind as conclusive proof of "how badly broken Britain really is".

The argument makes little sense, for it implies that greed and rule breaking is somehow an inescapable product of a particular constitutional arrangement, which of course is ridiculous. Sir Malcolm (who certainly behaved badly) is, of course, a Scot, but then Mr McEnaney would presumably argue that Unionism had somehow corrupted an otherwise decent sensibility.

More to the point, most of the phenomena Nationalists cite as proof of Britain's broken-ness exist in Scotland too (not least greedy bankers), but then assumption of the moral high ground was a central feature of the pro-independence case: Scotland good, Britain bad; or at the very least Scotland better, Britain worse. It was as reductive as it was insulting to No voters and those resident in other parts of the UK. Opposition leaders, as at the Kremlin a few days ago, are not being assassinated near Westminster.

Nevertheless many pro-independence arguments were salient because they contained elements of truth; it would take a brave pundit to defend the House of Lords, first past the post and the imbalance of political power, though that's more of a problem in England. (The lack of a written constitution I find less convincing, for lots of "broken" countries, like Haiti, possess codified constitutions.)

The UK is, therefore, a bit like Port-au-Prince's Oloffson Hotel, the ornate but faded institution immortalised as the "Trianon" in Graham Greene's comic novel The Comedians. Everything still works (apart from occasional power cuts), but beneath the elegance there's a sense of muddling through, sustaining the present with memories of its glamorous heyday.

In other words the UK, much like the Oloffson, is in urgent need of an upgrade, but thus far the refurbishments are proceeding - as ever - in a piecemeal fashion. The Smith Commission was hasty, a recent St David's Day agreement devolving some more power to Wales clearly a pre-election pitch, and the devolution of health powers to the Manchester city-region long overdue but administratively complicated.

Labour's Andy Burnham referred to the last of those upgrades as "Swiss cheese", which I presume he meant pejoratively despite the obvious retort that the Swiss manage their constitutional affairs a lot more effectively than the British. An ad hoc, unwritten constitution such as the UK's is bound to have holes; the challenge comes in filling them.

The period before an important general election usually produces state-of-the-nation tracts by leading commentators, and 2015 has proved no exception. Two of the best, How Good We Can Be by the Observer columnist Will Hutton and Back to the Future of Socialism by the Labour MP Peter Hain, both revisit earlier works (Hutton his own 1995 book The State We're In and Hain Tony Crosland's The Future of Socialism from 1956). Strikingly, both also reach similar conclusions.

"For all the egregious mistakes made on its behalf," writes Hutton, "the country is not a wasteland." Nevertheless, he contends, there "will be no re-energising of Britain without a complete makeover of the state." To Hutton the "outlines" of this are "fairly obvious": a federal UK, written constitution, regional English government and a balancing Upper House.

And, reaching a similar conclusion to that outlined in this column several times: "If Britain does not try to find its way to a more federal structure that works, expect the disintegration of the UK within the next twenty years." Peter Hain isn't as pessimistic, although he does regard as inevitable the recognition of a more "federal" UK, although "not one based upon an English Parliament". He sees Westminster retaining responsibility for macroeconomics, foreign affairs, defence and social security, but little else.

As Hain reflects, when Crosland first wrote The Future of Socialism it was "taken for granted that British socialism was a unitary idea applying across the nations", but 15 years of policy and electoral divergence has rendered that assumption redundant. Labour, therefore, ought not to fear promoting what Hain calls "countervailing sources of power", i.e. an elected Upper House and devolution in England. The state, be it Left or Right, ought to be "enabling" rather than uniformly prescriptive.

Will Hutton's book is bursting with ideas as to how the UK could be transformed into one of Europe's leading nations, not all of which emanate from the Left and at most of which even the SNP would balk, for example higher income and inheritance tax, as well as compelling private schools to accept a significant proportion of non fee-paying pupils.

All of this is to be welcomed, on a number of levels. For too long constitutional debate has been much too Scotland-centric, while genuinely radical policy debate usually plays second fiddle to visions as vague as they are utopian. Marry holistic structural reform of the UK to a bold policy agenda and you might end up with something both electorally attractive and worth fighting for.

Even without that the UK is not, as some would no doubt still contend, a "Nightmare Republic" of the sort Graham Greene described half a century ago. But it can - and arguably must - rejuvenate itself if it is to survive the 21st century or even, dare I suggest, the remainder of this decade.