The frustration among Wall Street analysts was palpable last week as Dell set out to explain the worse-than-expected drop in profits that battered shares in the world’s second-biggest personal computer maker on Friday.

Shares in the company fell more than 12 per cent the day after Dell disappointed investors who had been hoping for further evidence that the turnround launched more than 18 months ago by Michael Dell, chief executive, had begun to produce significant and, above all, consistent results.