The business - Patrick Hosking can't take Oliver Letwin seriously

Oliver Letwin, the shadow chancellor, cannot expect to be taken seriously while he draws a wage from

It's curious that while MPs and the media rightly spank the London mayoral candidate Steven Norris over his chairmanship of Jarvis, a different conflict of interest compromising a much more senior Conservative goes largely unnoticed. Oliver Letwin's continuing job at N M Rothschild - which pays him £100,000, the same as Nozzer is getting at Jarvis - is surely going to land him in hot water eventually.

The shadow chancellor is, I'm sure, an honourable man who would not be swayed one degree by his paymasters or their clients. But by taking the Rothschild shilling, he risks looking compromised whenever he opens his mouth. For his employer's tentacles reach into every corner of the financial markets and industry.

Letwin's territory is equally vast, covering not just the economy and state finances, but also trade and industry. Under the super-expanded role set up by Michael Howard, Letwin shadows Patricia Hewitt at the DTI as well as Gordon Brown at the Treasury.

Letwin is hopelessly compromised on virtually every financial subject. How can he appear objective on the telecoms industry, say, when British Telecom is an old Rothschild client? How can he appear impartial on the bidding wars among supermarkets when the Co-op and Waitrose, both Rothschild clients, help pay his salary? How can his view on energy policy be irreproachably disinterested when British Nuclear Fuels and National Grid both look to Rothschild for advice? How can he speak convincingly on Brown's dumping of Britain's gold reserves when Rothschild is a major player in the gold market?

The same goes for broadcasting, transport, defence procurement, insurance and privatisation: the BBC, the bus and train operator Arriva, Rolls-Royce, Royal & Sun Alliance and the Tote (a sell-off candidate) all use Rothschild and therefore indirectly pay Letwin's salary.

Letwin, dubbed "the left's favourite Tory" by the Guardian (whose parent company, by the way, is yet another Rothschild client), doubtless needs the money. He did say he would rather go out and beg than send his children to the local comprehensive in Lambeth. But Rothschild is not the right place to earn his money.

Letwin has two defences. First, he needs only four hours of sleep a night, so he can comfortably do both jobs. This misses the point; the problem is not with his capacity for work. Second, according to an aide, he will declare any possible conflict of interest. If he really does that, he's going to have to be disclosing potential conflicts all the time. Rothschild has 92 corporate clients, not to mention a string of tycoons whose personal finances it discreetly manages.

Despite Letwin's cuddly qualities - he admitted trying cannabis and is enlightened on homosexuality and immigration - there is still the residual suspicion that his heart resides in the bonkers transept of the Tory church. He did, after all, invent the poll tax and is best mates with John Redwood.

It's a pity because he made a cracking start with his first big speech as shadow chancellor, warning about the unsustainable growth in personal debt and about the damage Brown has inflicted on the savings culture in Britain. (We save half as much of our incomes as we did before Labour came to power.) Brown's penchant for means-testing has eroded the incentive to save. On the evidence of his first attack, Letwin has the weaponry and brainpower to inflict damage on Brown. But his credibility will suffer as long as he continues to earn a crust in St Swithin's Lane.

Heaven forfend that this column should stoop to cheap stereotyping, but our shopkeepers really aren't like other business people. Retailers are the luvvies of the business world. They revel in the theatre of the high street. They love to get bums on seats (they call it "store footfall"). And at this time of year they like to indulge in a near-hysterical bout of nerves. The run-up to Christmas is their first night. The anxiety is palpable. Everyone is hugely stocked up. A bad choice of merchandise can leave retailers with mountains of unsold stock and serious losses.

This year there's the usual uncertainty, exacerbated by stores that insist on getting into the seasonal spirit four weeks before their customers want them to. More stores than ever are holding pre-Christmas sales - Debenhams, W H Smith, Halfords, Matalan and PC World among them.

There is a bit of the camp, nervous Mr Humphries of Grace Brothers in every retailer. But the chances are that, come the end of the month, the tills will jangle more than ever and old Mr Grace will appear as normal in his bath chair with his dolly birds to declare: "You've all done very well."

Patrick Hosking is deputy City editor of the London Evening Standard