By any commonsense definition, the United States is already in recession, Warren Buffett (again) was saying yesterday. Never mind the official definition of two quarters of shrinking GDP, America is already displaying all the symptoms of a nasty slowdown and it could be deep and prolonged.

For some UK companies, the writing has been on the wall for some time, especially for those reliant on the US housing or construction industries, such as Wolseley and Tomkins and, of course, HSBC.

But the gloom is now fast spreading to the manufacturing sector. US sales falls reported yesterday by two major manufacturers, Ford and Toyota, provide fresh evidence that the American consumer is deferring purchases of big-ticket items or at least trading down.

Yesterday's rise in the crude oil price to another record can only curdle confidence further. US factory activity contracted last month to its weakest level in five years. UK component suppliers to the US, already struggling because of the weak dollar, face more headwinds.

Pearson shares were sold off yesterday on fears that US demand for school textbooks could dwindle. It would take a major downturn for tax receipts to be squeezed sufficiently for states to make budget cuts in education and for education authorities to seriously cut back on books.

The hard fact is that in these uncertain times, no one doing business in America is going to be immune from investor jitters.

patrick.hosking@thetimes.co.uk

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