A FEW years ago, David “two brains” Willetts published a book called The Pinch. It analysed the baby boom of the two decades following the war, and argued that the biggest, richest generation the UK had ever known had attained a dominant position at the expense of their children.

Of course it was supposed to be provocative, especially so coming from a Conservative frontbencher, whom one might expect to be a diligent courter of the “grey” vote. But Willetts was thinking outside the box, challenging the received wisdom of both his colleagues and opponents.

And of course he got absolutely nowhere. Although as I moaned last week, substantive issues have generally been absent from an increasingly vacuous and shrill General Election campaign, the so-called triple lock guarantee for state pensions has surfaced now and again, not least as the sort of differential policy Scottish Nationalists delight in wielding against the wicked Tories.

When reports surfaced a few weeks ago that the Prime Minister was considering ditching a pledge that state pensions would rise in line with inflation, average earnings or by 2.5 per cent – whichever is the higher – there was the inevitable backlash from Tory backbenchers and pensioner rights groups.

Naturally, Conservatives worry that their expected landslide on June 8 might be a little bit smaller as a result. In March, the Chancellor, Philip Hammond, promised it would remain until 2020, at that point the date of the next election, with a review ahead of that date. Obviously that timescale has been torn up, and perhaps Prime Minister Theresa May sees an opportunity (as a result of that anticipated landslide) to shed costly policy commitments associated with her predecessor.

Of course the SNP, whose nose for a grievance is acute, scented blood and went in for the kill. A few weeks ago, their Westminster leader Angus Robertson asked the Prime Minister what he called “a pretty simple yes-no question” as to whether the triple lock would be kept if the Conservatives remained in government. In response, Mrs May gave one of her typically stuttering responses, merely promising that “under a Conservative Government, pensioner incomes would continue to increase”.

Campaigning last week, Nicola Sturgeon drove home the point, pledging that every SNP MP would vote to protect the triple lock, before challenging the Conservatives to set out their position. A U-turn, she added, would amount to a betrayal of pensioners. Mrs May, however, is right, and Ms Sturgeon is wrong, the policy should at the very least be reviewed as soon as possible, preferably as a precursor to a complete overhaul.

Anyone without a vested political or financial interest generally agrees. For example, Ros Altmann, a former Tory pensions minister, believes the policy isn’t working properly, is illogical and leaves out the poorest oldest pensioners. She, at least, appears to be familiar with the Willetts argument, and hopefully the Prime Minister is, too.

The rationale for the SNP’s position, meanwhile, is fairly easy to discern. During the first referendum campaign the Yes side got their fingers burnt over pensions, while polling continues to show that older voters, especially older female voters, remain sceptical about the independence proposition. So, if there is a second referendum (and I reckon it’s now a bigger “if”), the Nationalists need more of those voters on side, thus the First Minister beating the drum as loudly as she can at this stage.

And being a reserved policy, it’s viewed wholly tactically by the Scottish Government, which is conveniently shorn of any responsibility to actually deliver or maintain the triple lock, a Tory-Lib Dem policy that, ironically, the SNP now considers sacrosanct. Don’t bother asking how an independent Scotland would fund such a generous policy given its ageing population, the rejoinder to that would be of the playground “stop talking Scotland down” variety.

In his book, Willetts argued that if political leaders weren’t willing to compromise, then the younger generation would end up being taxed more, working longer hours for less money, have lower social mobility and live in a deteriorating environment simply in order to maintain their parents’ quality of life. Now I’m pretty sure Nicola Sturgeon wouldn’t consider any of that to be acceptable, yet it’s the logical outcome of her support for protecting pensioner income no matter what.

It is, unavoidably, a tricky policy to change. Once implemented, any populist policy (ie the similarly daft Council Tax freeze) becomes very difficult to reverse or tinker with and, of course, it’s highly unlikely the older generation will take kindly to the idea of making the sacrifices necessary for a more equal distribution of Britain’s wealth, but unless this country is entirely governed by focus groups none of those are compelling reasons to maintain the status quo.

Usefully, Naomi Eisenstadt, long one of the few sane policy voices associated with the Scottish Government, recently became the latest expert to say the triple lock should not automatically be protected. Already on record as being critical of other universal benefits such as free travel, the winter fuel allowance and TV licences, the First Minister’s adviser on poverty said pensioners were enjoying the benefits of a strong economy of the past but carrying the least burden of current economic weaknesses.

Indeed, a report Ms Eisenstadt issued last year showed that while 22 per cent of Scottish children and 19 per cent of working-age adults lived in poverty, the figure for pensioners was just 12 per cent. Twelve per cent too many, you might think, and you’d be right, but what on earth is the logic in continuing to prioritise those 12 per cent over the 41 per cent from younger, economically-active generations?

Ms Eisenstadt also said the “trick” for policy-makers was finding a way of targeting benefits at those who need them most without creating more bureaucracy, and that’s surely not beyond the wit of humankind. The SNP, however, are wedded to the bogus panacea of universality, an approach (with notable exceptions such as the NHS) that ought to have been buried back in the 1970s.

But older voters, of course, typically turn out to vote in higher numbers, which explains why Labour and the Liberal Democrats (who claim credit for its introduction) also support maintaining the triple lock. It’s just a shame David Willetts won’t be a member of the UK Government this time next month.