Yet there is a logic to this. Almost a year ago, the director of MI5, the UK security service, warned financial services companies that Chinese state enterprises were attempting to break into their systems. Presumably the Chinese stole the strategic plans and sophisticated risk management systems of Lehman Brothers, Bradford & Bingley and Landsbanki. The Bush White House was the obvious next step.

This summer, the systems of the presidential campaigns were breached and large documents downloaded – Governor Palin’s expenses from Saks Fifth Avenue?

Yet cyber warfare is no laughing matter. Russia is widely presumed to have been behind cyber attacks on Estonia. These were closer to acts of war than acts of espionage; bank and newspaper websites were attacked and the phone line to the emergency services went down.

The Chinese are thought to have infiltrated not only the White House systems but, last year, those of the Pentagon. The security breach was of unclassified systems, not the more secure classified systems. One lesson is familiar: never put sensitive information in an ordinary e-mail.

Electronically enabled espionage and sabotage is becoming ever more sophisticated. This is an issue that the world’s great powers will have to address. The use of cyber warfare, which can destabilise financial systems, the telephone system or the energy grid, may need to be governed by treaty. That will not be easy: attackers are hard to pinpoint; no satisfactory legal framework exists; and, of course, the US is bound to be on the cutting edge of these technologies.

In the meantime, we can but hope that the Chinese restrict themselves to reading whatever it is that occupies George W. Bush these days