‘It surely can’t be right that a teacher, or care worker, or research scientist, is expected to pay the same graduate contribution as a top commercial lawyer, surgeon or City analyst… whose graduate premium is so much bigger.’

So says Vince Cable, who last week unveiled proposals for the biggest overhaul of Britain’s universities for a generation. The Cabinet minister responsible for higher education has asked Lord Browne, the former businessman conducting a review of student finance, to look at a variable graduate tax which would see higher earners pay more to fund their tuition.

One might recast Cable’s statement for the Gazette’s purposes. It surely can’t be right that a gifted law graduate who takes a low-paid but prestigious human rights job ultimately pays the same graduate contribution as an equally gifted contemporary who becomes a magic circle trainee and eventually attains millionaire status. Can it?

A degree confers a financial benefit exceeding £100,000 net of tax over a working life relative to a non-graduate. But this is an average; for the magic circle trainee who makes the grade, their degree is going to be worth a lot more than that.

Like any government policy perceived to weigh heavily on the middle classes (however they are defined), this one attracted a volley of wrong-headed tabloid misrepresentation. One serial offender inveighed preposterously against another government ‘stealth tax’ – when income tax is the one tax among many that plainly doesn’t qualify for that label. ‘Brighter’ students who get highly paid jobs will be taxed more, it fretted, taking it as implicit that ‘bright’ people are solely motivated by money and always opt for a highly paid career.

We are also expected to acknowledge that jobs that do pay generously are invariably peopled by mental Olympians (investment banking, anyone?).

That Vince Cable has picked up this baton reflects an odd separation of powers that sees higher education fall within the purview of the Department for Business, Innovation and Skills (BIS). So it was timely that his speech followed an update from BIS on how it is working with employers to widen access to the professions for under-represented groups.

‘The membership of professions needs to reflect the diversity of modern society,’ the BIS website says. ‘It is in employers’ own best interests to recruit from as wide a range of applicants as possible.’

Quite so. Yet, despite these warm words, we know from Alan Milburn’s 2009 report on social mobility in the professions that the law is becoming more exclusive, not less, because of rising material inequality.

So is Cable’s plan to be commended? Or if not commended, then pursued as the least worst option? After all, there is a consensus that funding tuition costs from general progressive taxation – a policy that benefited Cable’s own generation so handsomely – is a non-runner. He has promised ‘deep cuts’ in public spending on universities and made it clear students will pay more.

We already have a graduate tax of sorts; the student loan scheme, under which tuition fees are repaid after graduation. But as Cable says, this is a ‘poll tax’ that takes no account of the income of the graduate. Students pay back the same £3,225 a year.

It is easy to predict what will happen when the tuition fee cap is lifted and aspiring students are confronted with the reality of incurring debts of at least double the £20,000 they run up at present. Many will only go to university if their parents will support them, potentially depriving the professions of legions of talented people. And even those who are prepared to countenance a massive financial hangover will go into the best-paid job they can find as quickly as possible after graduation – regardless of whether they want to, or indeed whether it suits their talents. A graduate tax will not serve as such a powerful psychological deterrent to higher education.

Browne may yet rain on Cable’s parade and one must remain sceptical. Not least because, to get his plan through, Cable will have to persuade a Conservative-dominated government to vote for higher tax on high-earners. Now that really would be ‘new politics’.

Paul Rogerson is editor-in-chief of the Gazette