ANYONE making an expensive purchase, then discovering the items in question are already three years late, not what was ordered, twice the price that was quoted, and with no sign of delivery in sight, is entitled at the very least to a full explanation.

You are that buyer. The shambles surrounding two new ferries to serve Arran and the Hebrides now has the Scottish taxpayer on the hook for at least £200 million, in what is merely the latest example of an embarrassing and costly public project that has run aground.

Ferguson Marine, which won the contract in 2015 and went under last year with debts of £49 million before being taken into public ownership, blames the Scottish Government and CMAL, another state-owned company that owns the ferries run by CalMac. CMAL claims that Ferguson began work before agreeing final specifications, and that cost overruns were its responsibility.

Meanwhile, CalMac says that it never wanted dual fuel vessels, using marine diesel and liquefied natural gas (LNG), and Jim McColl, the industrialist who took on Ferguson’s in 2014, says the system would never have provided a benefit.

The Scottish Government stands accused of having insisted on LNG as a green gimmick, and of prematurely announcing the order to steal a march on a Tory spending commitment at Faslane, made on the same day by the then Chancellor, George Osborne.

If, as the Scottish Government’s former adviser Luke van Beek suggests, there was a breakdown in communication, and that the brief for the project was dangerously vague, it can certainly be charged with having failed to provide adequate scrutiny of how public money was being spent, and to have stepped in to prevent matters becoming worse.

After the fiascos at ScotRail and the hospital builds in Glasgow, Edinburgh and now Aberdeen, this is becoming a dismally familiar complaint. The latest mess – which holds up to ridicule both our proud shipbuilding heritage and the basic competence of Holyrood – is a particular embarrassment, and demands an urgent public inquiry. This, too, is a depressingly familiar call.

But when the Government seems to have been incapable, in a host of costly public projects, to exercise even the most minimal oversight or accept a basic measure of accountability, it is unavoidable.

Ministers have been far too ready to make excuses, dodge responsibility and – always a favoured tactic – accuse critics of “talking Scotland down”. If the SNP wishes to demonstrate that independence is a credible political option (and no one disputes that there should, at the very least, be a presentable argument to be made for an option with the support of half the population), it needs to begin operating with the basic level of competence citizens expect and deserve.

The greatest service the SNP could perform for the nationalist cause is not to attempt to rerun the last referendum, nor to manufacture grievances to lob at Westminster, but to give the electorate evidence that politicians at Holyrood are capable of performing the tasks fundamental to government.

That means upholding standards in public services, demonstrating responsible stewardship of the taxpayers’ money, ensuring infrastructure projects deliver the intended result and provide value for money and, above all, accepting that the responsibility for failure ultimately rests with ministers.

Examples such as Crossrail and HS2 demonstrate that such failings are not unique to Scotland; they are a perpetual risk in all government spending. But that is why the public is entitled to expect ministers to be vigilant against waste, delay and a failure to deliver. Scotland’s record is undeniably poor.

The Government at Holyrood is gaining an unfortunate reputation for expensive failures of this sort. Their apparent casual disregard for their basic duties, and for what the Scottish people have a right to expect, is a disservice to Scotland as a competent and capable nation which can attend to its own affairs. That, if nothing else, should alarm the SNP, since it is an indictment not only of the competence of their current administration, but of their fundamental ambition.