The board insisted it remained committed to the company's business strategy but wanted a chief executive who would provide more �ghands-on�h leadership and drive profitability.

HP's shares rose more than 6 per cent to $21.45 in midday trading in New York.

Ms Fiorina had staked her reputation on the $19bn acquisition of Compaq Computer in 2002, but the company's server, storage and personal computer businesses have all since struggled.

In addition, Ms Fiorina had drawn criticism for what was seen as an imperious leadership style.

HP's shares have fallen by about 50 per cent since Ms Fiorina's appointment and continue to trade at a discount to rivals amid concerns about the company's ability profitably to execute its strategy.

Several Wall Street analysts have called on HP to spin off its highly profitable printing business or sell its PC unit, arguing that the company was being squeezed between IBM's high-end services strategy and Dell's low-cost PC manufacturing.

Steve Milunovich, the Merrill Lynch technology analyst who last year called for a break-up of HP, said the board's declared intention to continue with its existing strategy made any big changes in direction unlikely.

He added, though: �gI think bringing in a new CEO increases the long-term chance of breaking it up.�h HP named Robert Wayman, chief financial officer, as interim chief executive and said it would immediately begin a search for a permanent successor.

�gWe are looking to accelerate the growth of the company and we believe that requires a lot of hands-on execution,�h said Patricia Dunn, a HP director who was named non-executive chairman of the board. Ms Fiorina will receive a $21m severance package. �gWhile I regret the board and I have differences about how to execute HP's strategy, I respect their decision,�h she said.

Her departure brings to an end a controversial leadership of what remains a Silicon Valley icon. The Compaq merger proposal sparked a high-profile battle of wills with Walter Hewlett, then board member and son of co-founder William Hewlett, who said the deal would dilute the value of HP's printing business.

Ms Fiorina won over investors by a narrow margin and earned the grudging respect of doubters by integrating the two companies ahead of schedule. But many investors have been reluctant to endorse her bigger-is-better strategy, which encompasses corporate computing, services, printing, PCs and consumer products.

Wall Street grew dismayed by HP's tendency to post several strong quarters, only to disappoint by falling short of expectations.

Doubts about Ms Fiorina's performance were heightened last August, after the company missed its third-quarter targets. Sales and earnings recovered in the fourth quarter and Mr Wayman indicated that HP was on track to hit its targets when it reports again next week.