HOWZAT

“What Gordon has achieved is a machine that keeps on enlarging and taxing and regulating and keeps producing extremely low output in comparison to input.” That, in turn, effects productivity growth as a whole across the economy.

Letwin’s alternative? Well, he has yet to reveal his own detailed fiscal plans for the economy, but he has pledged that he will maintain the growth in spending on schools and the NHS while keeping taxes at current levels and, possibly, if conditions allow, reduce them.

How will he do that? First, by taking 100,000 jobs out of the civil service over six years — all by natural wastage — then by eliminating inefficiencies.

Will voters buy it? That’s a tough question. Letwin argues that there is an alternative to an ever-larger state, that more control must be passed to the individual, that we must be able to choose our schools and hospitals, and makes a good case for it, but sometimes the blizzard of words leaves you snowblind for detail. And on a personal level, there’s a side to Letwin — the one he sells as his erudite Honest Joe approach to politics — that actually can make him seem rather divorced from reality and, occasionally, a bit of a twit.

Hence those stories that he was, allegedly, sent into hiding at the last election after inadvertently admitting that the Tories would cut public spending by £20 billion. Then last year he told the press he would rather be a beggar than send his children to state school. Some rather admire him for his candour, but it’s not exactly going to mop up the less-well-off vote.

Likewise, when I ask him how much he earns as shadow chancellor, or even as an MP, he lets out a high-pitched giggle and says he has no idea (MPs are paid £56,358). And recounting his hobbies, he goes: “Oh I ride, I walk, I read and, most of all, I talk, hahaha.” At times like this, when the foppish laugh takes over, Honest Joe seems to mutate into Mad King George. No wonder critics say he lacks political bite.

But colleagues at Rothschild, where he worked with John Redwood advising foreign governments on privatisation, say he is tougher than many think, and a good business-getter.

“Oliver is hugely intelligent and highly numerate,” says Nigel Higgins, head of investment banking at Rothschild, “but most importantly he has the ability to simplify and explain things, without it seeming glib.”

His 17-year stint at Rothschild — he resigned as a director only in December — was certainly lucrative. Letwin and his wife, Isabel, who works as a lawyer, have a nice home in his west Dorset constituency, where he plays tennis, and another in London’s Kennington. He drives not one, but two Land Rover Discoveries (one blue, one green). “I use one in Dorset and the other for running up and down,” he explains, not thinking it the slightest bit odd.

So what motivates him? “Oh I adore this,” he says, waving his hands around. Others suggest that he was strongly influenced by his mother, Shirley Letwin, who was a formidable right-wing academic and fascinated by politics. They note that since his mother died, Letwin, who once mirrored her adherence to free-market policies, has actually got rather more liberal.

Now he’s addicted to the public forum and it makes his coming confrontation with Gordon Brown all the more eagerly anticipated. Both share a mastery of the brief but the contrast in styles — the dour anorak versus the genial boffin — couldn’t be greater. “Oliver is my favourite person in British politics,” says Redwood. “So nice, so decent and so friendly.”

So nice that it’s hard to believe Letwin will be able to land any punches on the chancellor. When I notice a fat tome about Gordon Brown, on top of the book pile on his table, and joke “know thine enemy”, he looks positively affronted.

“Enemy?” says Letwin, “No, not enemy. ‘Opponent’, I think, might be a better word.” Then he beams a vicar-ish smile. No doubt he will take great pleasure in surprising us all in the coming months.