I suppose it had to happen. As a society we always want someone to blame for our ills. Usually it is someone else. But now we, the baby boomers, the biggest, best-off generation ever, have to blame ourselves.

Having shaped the culture and values of the late 20th century, those of us who were born between the late 1940s and the early 1960s soaked up the benefits of generous company pension schemes, leaving nothing in the pot for our children.

We hoovered up housing when it was affordable, then benefited from a massive house-price boom. Rather than saving some of that money for future generations, we borrowed against our assets and spent it all, a big black mark against us when it came to the recent banking crisis and the nation's current ability to invest in its future.

Our epic levels of consumption pose a huge environmental threat to subsequent (smaller) generations who will have to support us as we live longer, even though they entered the workforce just as globalisation and cheap labour were pushing down wage rates.

Shadow Cabinet member David Willetts, who currently speaks on higher education and family policy for the Conservative Party, has been quick off the mark in recognising our role in the parlous financial state we are bequeathing our children. His book is already out, while the penny is only just dropping for many other writers and commentators.

His legendary "two brains" have drawn together a vast array of research evidence combined with some interesting but not always convincing personal theories about what the demographic statistics show and what we should do about the fact that, after half a century "sailing with favourable tailwinds", we will spend the next few decades battling against "demographic headwinds".

And that's the tricky bit. Willetts's central argument is that we need a new social contract that will encourage delayed gratification and strengthen reciprocity across generations at a time when, as he puts it, "the trend towards atomisation looks unstoppable".

It was at this point that I started to wish he wasn't a front-bench politician. He is an engaging person and an original thinker in a world of identikit MPs, but his political agenda and personal beliefs prevent the book being as objective and candid as it should be.

He acknowledges that a first step to encouraging a social contract between generations is to embed that contract within them. He is probably right that politicians can't just "pour social cement over atomised citizens to try to stick them together so they cooperate". But even in his vision of cooperative behaviour being like "dry stone walling held together by its inner structure", someone has to champion the social bonds that make up that inner structure.

But the messages and policies from the politicians over the last 30 years have been distinctly mixed and may have exacerbated the worst tendencies of the boomers. The headlong rush into home ownership was encouraged and celebrated  there is barely a mention in the book of the effect council house sales had on the post-boomer generation's chances of getting a home, let alone a foot on the ladder.

Personal choice, competition and aspiration have been emphasised at the expense of collective activity. Margaret Thatcher's famous assertion that there was no such thing as society was qualified by her belief that instead there were individual men, women and families and, buried away in Willetts's bleak analysis of a nation with too many divorces, single parents, childless singletons and transient relationships, is an admission that many of those individual baby boomers care passionately about their children's futures.

We now spend more time with our children than ever before, despite the increase in two-earner families, and many people invest heavily in what Willetts calls "a kind of parental arms race" to secure their children competitive advantage over others. That investment isn't just in education but in being "the bank of mum and dad", in helping children on to the housing ladder, then bequeathing valuable properties, possibly with an imminent reduction in inheritance tax to give the personal, rather than collective, intergenerational reciprocity a further push.

Does Willetts really believe that we can "nudge" a new social contract between citizens that will spill over into a willingness to care collectively for future generations, while there are such glaring disparities between the winners and losers in this race? He envisages a world where there is more trust between citizens and generations, but the resentment that results from seeing some people achieve and acquire at the expense of others is surely integral to lack of trust in both vertical and horizontal generational relationships.

It is possible that the recession will make all of us more thoughtful about the future and more wary of instant gratification; but if we are going to become less atomised and start caring collectively for each other and future generations, we will need a bigger and clearer political message from our politicians than Willetts is able or willing to articulate in this book.

Fiona Millar's The Secret World of the Working Mother is published by Vermilion.

David Willetts is a rare creature. Britain does not produce many public intellectuals. To find one lurking deep in the jungle of Westminster politics is little short of an anthropological miracle. But with this book, Willetts, a frontline Conservative politician, has confirmed his status as the thinking person's MP.

The Pinch sets out to show how the baby boomers  those, like Willetts, who were born between 1945 and 1965  have "stolen their children's future" through their cultural, demographic and political dominance. Willetts does not quite succeed in proving this charge of intergenerational theft. But in marshalling his case he takes you on such a fascinating journey through British society that you do not feel remotely shortchanged.

His stated thesis is that the big generation of boomers has concentrated wealth, adopted a hegemonic position over national culture and failed to attend to the needs of the future. They have, in effect, broken the inter-generational ­contract. It is certainly true that the boomers have done well out of the welfare state, being set to take out, Willetts suggests, approximately 118% of what they'll put in. But this makes them no worse than ­previous generations, including those born between 1900 and 1920.

There is also no doubt that the monomaniacal British obsession with home ownership, while far from being a new phenomenon, has so far benefited the boomers rather more than the generations on either side. At the same time, the rise in immigration since the mid-1990s has held down wages for Generations X and Y (or those born between the mid-60s and the millennium) who would otherwise be benefiting from being in a smaller cohort and therefore a tighter labour market. It is also true that the boomers haven't been proactive enough on climate change  indeed, Willetts says too little about this  but it is hard to argue that they can be singled out on these grounds.

Willetts is unsure whether the ­boomers are a bad generation or just a big and lucky one. At one point, he insists that "generational name-calling" is unhelpful and that the issue at hand is simply a demographic one. But at other points, he labels the boomer generation a "selfish giant", which sounds like ­name-calling to me. The main problem facing him is the absence of hard data. There is good academic research in the US on "inter-generational accounting", but no equivalent here.

Willetts is candid about the fact that "there are no authoritative estimates of the distribution of the £6.7 trillion of wealth in our country between the ­different age groups" and relies instead on the assertion that "there are good ­reasons to believe" the boomers have got more than their fair share. There are some reasons to believe this, but it is also likely that the recent financial crash will alter any generational distribution of money, since the boomers are retiring just as the value of their pension assets has been sharply knocked down.

Willetts might have done better to take as his main theme the links between family, education and social mobility, since on these issues he is on firmer ground. In fact, his title could just as easily have been The Big Grab: How the Rich Are Using Money and Marriage to Buy the Future for Their Kids. His ­opening ­chapter is a tour de force, a brief, brilliant history of England's social architecture. He shows that far from being a modern invention, the nuclear family is a long-standing feature of Anglophone societies. (We are, he says, "the first nuclear power".) The idea that we used to live in big, warm, noisy My Big Fat Greek Wedding-type families is a myth. "Think of England as being like this for at least 750 years," he writes. "We live in small families. We buy and sell houses. We go out to work for a wage."

The English have a private, market-based idea of property, in contrast to the familial property forms of our continental neighbours. Over a 44-year period in Leighton Buzzard, more than 900 houses changed hands. Two-thirds were sold to someone outside the family, rather than being passed down. The years in question? 1464 to 1508.

By contrast, the large familial networks of continental Europe act as the institutional anchor for property ownership and transmission, as well as for the formation of businesses and the provision of welfare. Willetts speculates that the property-managing function of French families may explain why romantic love there is more often associated with extramarital relationships. The orientation towards family-owned firms in Germany helps to explain the strength of the Mittelstand, the medium-sized, locally rooted layers of corporations.

Willetts does not at any point fall victim to the awful if-only-we-were-more-like-the-continentals lament. He does not want to alter our social DNA. But our particular social economy has two important consequences. First, the smallness of our families puts a greater emphasis on non-familial civic institutions. Small families need civil society more. This is why medieval guilds, trade unions and churches have played such an important role in our history.

Second, the welfare role of government is greater in a society marked by a highly privatised notion of property and small families. Breadwinning men are less likely to have family resources to fall back on, so need out-of-work benefits. This system worked reasonably well until the rise in divorce rates in 1970s and 1980s. Then, millions of women, many with dependent children, suddenly became reliant on the state. As Willetts puts it: "A welfare system that was ­originally designed to compensate men for loss of earnings is slowly and messily redesigned to compensate women for the loss of men." And everybody  but ­especially women  ends up poorer. This is why Willetts, certainly no reactionary, is so pro-marriage.

Strong parental relationships also influence children's well-being, which in turn affects the chances of upward social mobility, another of Willetts's preoccupations. Drawing on the very latest and best research, Willetts shows how the middle classes are tightening their grip on the opportunities available for the next generation. The professions are all but sealed off from the poor: "The competition for jobs is like English tennis, a competitive game but largely one the middle classes play against each other."

In general, this is a remarkably non-political book; David Cameron is mentioned just once. But ­Willetts does argue strongly for a vouchers scheme in ­education, weighted in favour of the poor, in order to break the middle-class stranglehold on the state education ­system. And the explanation for the flat-lining of social mobility brings Willetts back to social structures and, in particular, the trade-off between gender equality and class equality. The principal beneficiaries of the expansion of higher education have been the daughters of the middle class. Six per cent of girls born into low-income families in both 1958 and 1970 went to university; for girls born into richer households, the rate rose from 21 per cent to 36 per cent.

"Educational upgrading"  the increase in the numbers of young ­people getting qualifications  accounts for 40 per cent of the fall in mobility for women between 1958 and 1970. This is, as Willetts says, a shocking statistic. The expansion of higher education, far from improving social mobility, has actually made it worse.

Women graduates marry male graduates and this trend towards "assortative mating" has increased in recent years, which means that on a household level, inequality is bound to rise. The narrowing of the gender gap seems to have widened the class gap. As Willetts puts it: "Feminism has trumped egalitarianism." And not just for one generation, either: just 5% of degree-­educated mothers split up from their partner before their child's third birthday, compared with 42% of mums with no qualifications.

Willetts manages to synthesise these social trends into a coherent and engaging narrative, successfully mixing vignettes from South Park and The Simpsons with statistics from the British Household Panel Survey. Most important, when it comes to social and economic research, Willetts really does know his stuff.

David Cameron has lately been engaging fruitfully with external political thinktanks (including, I should say, Demos). This is greatly to his credit. Let's hope he recognises that in David Willetts he has a one-man thinktank right under his nose.

Richard Reeves is the director of Demos