Unjust Rewards, By Polly Toynbee and David Walker

The right-wing hacks will hate her for it, but Polly's bang on the money in this blistering polemic

It's widely believed – at least among readers of The Spectator and the Telegraphs – that The Guardian's high-minded social affairs columnist Polly Toynbee owns half of Gloucestershire and a considerable slice of Tuscany. Richard Littlejohn of the Daily Mail frequently fantasises about her in a pole-dancing role. And a fortnight ago, The Times' winsome restaurant columnist Giles Coren described her as a "sour old Trot".

She must be doing something right. What exactly is it, and why are they so worked up about her? Toynbee's new book, co-written with her partner David Walker, on the growth of inequality in Britain, will give you something to go on. Unjust Rewards is an entirely serious book about an entirely serious subject, the rise of the unthinkably rich over the last two decades. It's what the "Cameroons" call the "Broken Society" theme. And although the Cameroons would reject her conclusions – that winner-takes-all rewards pull the nation apart, that we should collect the taxes the rich are supposed to pay anyway and that we should create an anti-tax avoidance culture as opposed to a Leona Helmsley one – they clearly take it seriously.

Unjust Rewards isn't a barrel of laughs. (Toynbee is constantly described as "humourless", as if stand-up experience was a key requirement for broadsheet social policy coverage.) It's evidence-based, and deploys uncomfortable but incontrovertible facts and social science sources very effectively. Thus the deeply unfunny fact that the UK pay gap between the best and worst paid employees has widened vastly. The average FTSE 100 CEO's earnings went from an average 17 times ordinary employees' pay in 1988 to 75 times the average in 2008; ie the gap has more than quadrupled, according to that hardcore commie source the Institute of Directors.

This particular approach – no jokes, really knowing your way round the stats, clear recommendations at the end, isn't the traditional right-wing controversialists' way with an argument. They prefer the Boris approach: good jokes, colourful language and a lot of ancient history. Anything in the social science area is "grim" and socially suspect. She must be Polly from the poly. But she isn't, of course; and that's what makes it so much worse. Polly's a lady, upper-middle-class, from the intellectual 19th-century Oxbridge purple – Toynbee the critic, Toynbee the Hall, a strand from an earldom – definitely PLU. So Polly's seen as a class traitor because she "bangs on" about unfairness, because she thinks that the minimum wage should be higher and because she drives inexorably to the conclusion that now, more than at any time since 1945, class and family are destiny. In terms of real-life chances rather than innate talent, it's nurture that matters. The baby-boomer meritocrats have made sure that another generation won't make it up and out in the same way.

Toynbee and Walker shred all the familiar special pleading. Financial trickle-down simply doesn't happen without tax intervention. The constant argument for super-normal rewards – that you've got to retain top people in an international super-labour market – doesn't bear much examination either. The world may like our actors and designers but it isn't constantly waiting at the door for our businessmen – we're more likely to import CEOs, bankers and lawyers than export them.

But of course it doesn't look like that from the top. In the first chapter Walker and Toynbee describe what they hear from a group discussion in the City among bankers and lawyers earning anything from £150,000 up to £10m. These people have entered a different world, but they think they're ordinary middle-class. Their idea of the nursery slopes of high pay in the population at large, the entry point to the top 10 per cent of earnings, is £162K (it's £39,825, where the top 40 per cent tax-band starts). And they thought poverty began at £22,000, only just under median national earnings. The official poverty line for a childless couple is £11,284.

It all sent me back to Hard Work (2003) Toynbee's scrupulously honest account of her time working undercover in a variety of minimum-wage jobs. Taken together, the two books help put growing inequality and social distance on the agenda and make it hard for the last City PR left standing to argue that UK 2008 hasn't been stretched to breaking point.

The polls are now showing growing concern about inequality. People here and in the US want the banker sellers and buyers of the poisonous derivatives behind the credit crunch banged up for a long time rather than home free with massive pay-offs. That extraordinary American book Richistan, which suggested the New Seriously Rich were so far from the rest of humanity they lived in their own imaginary nation-state, Robert Peston's recent Who Runs Britain?, and now Unjust Rewards are all focusing attention on the seriously rich. In tough times the Rich List Groupies are drifting away.

In 2001, just after Auberon Waugh, the poster boy of the anarchic Right, died, Toynbee dissed him comprehensively in her Guardian column as nasty, snobbish and misogynistic, "a reactionary fogey whose sneers seriously damaged this country". She drew a cruelly sharp group portrait of the Right-Wing Gentleman Hack set, its language, dress-code retro-affectations and its sustaining fantasies. They've hated her ever since. But Matthew Parris admitted in The Spectator that "her essay was sincere and brave and contained an awful truth. It was one of the finest pieces of journalism I have read." Unjust Rewards should be compulsory reading for anyone on £162,000 and over.