THREE-AND-A-HALF years after student protestors smashed up Conservative HQ, the policy they were fighting that day is also falling apart.

Yes, the controversial hiking of tuition fees to £9,000 a year is heading for disaster – although not in the way that was predicted at the time.

Back in 2010, the main criticism of the toxic policy that made Nick Clegg such a target of voter fury was that it would deter young people from attending university.

But, as the deputy prime minister enjoys pointing out, student numbers are up, as is – thanks, perhaps, to expensive bursaries – the proportion of youngsters from poorer families.

So, what’s the problem? Well, it is the extraordinary fact that a system to raise money looks like leaving the taxpayer with an even bigger bill than the one it replaced.

When the brilliant minds behind £9,000-ayear fees dreamt them up, they expected that 28 per cent of the loans to allow students to pay them would have to be written off.

But, the official estimate is now that 45 per cent of loans will have to be cancelled – within touching distance of the 48.6 per cent that will tip the scheme into the red.

Parliamentary figures revealed that for every £1 invested on teaching in universities, a staggering £7.50 is being spent on writing off students’ debts.

It’s crazy. Would-be students are forced to contemplate 30 years of enormous personal debt, only for almost half of them to never earn enough to repay it.

And are universities rolling in cash? No, of course not – because teaching grants have been slashed or axed to compensate. What a monumental cock-up.

There is a growing realisation of this, with the Daily Mail warning student finances are “in chaos”, while the Conservatives – determined to keep digging in a hole, it seems – are exploring further fee hikes at elite universities.

Meanwhile, Labour has made it clear that £9,000 fees will go if the party wins back power, after going very quiet on the subject.

During the Labour leadership race, Ed Miliband argued for dumping fees altogether in favour of a graduate tax that would ensure high-earners paid back more.

In an interview last week, he promised a “radical offer” in his manifesto – fuelling speculation that Labour will go for a graduate tax.

This would, it is argued, end the unfairness of the rich contributing less by paying off their loans faster, thereby avoiding interest on the debt.

And it would eliminate the fear of a “mountain of debt” that deters some from applying to university in the first place.

But I’m told senior Labour figures fear it may be too complex to switch to an entirely new system, which may see a compromise of a lower fee cap – say £5,000 – instead.

I hope not, because a graduate tax – an extra two per cent, for 40 years, is one suggestion – looks the fairer option for replacing the turkey of sky-high fees.

KEVAN JONES has “great respect for the North-East Chamber of Commerce” – but it may wish to ask the North Durham MP about this comment about its backing for the recent Budget.

He told the Commons: “I have never seen it disagree with any Budget, because, understandably, it likes to keep in with the Government of the day . . .”