Carly Fiorina, the chief executive and chairman of Hewlett-Packard and possibly the most powerful businesswoman in the world, has left the American computer and printer giant following a long-running series of boardroom rows.

Ms Fiorina, pictured, pushed through the controversial $19 billion (£10bn) takeover of rival Compaq Computer in 2002. The move, which was designed to remake H-P into a PC powerhouse, was bitterly contested by some on the company board.

H-P, which has annual revenues of $80 billion (£43bn) a year and is the eleventh-largest corporation in the United States, has since lost ground in the PC market to the global leader, Dell. It also faces stiff competition from IBM in the IT services arena.

Shares in H-P rose by as much as 12 per cent in early New York trading on the news of Ms Fiorina's departure.

Criticism of the Compaq deal has pivoted on the fate of H-P's highly profitable printer business. Last year, the company's printer and PC divisions pulled in around $24 billion in revenues a year each. However, the first made profits of $3.8 billion and the second of only $210 million. Before the merger, H-P shareholders owned all of the of the successful printer division. Afterwards, the company retained only 63 per cent of it.

Ms Fiorina took the reins of the company in July 1999 and quickly began to shake-up H-P, which was widely perceived as a venerable but slow-moving Silicon Valley giant. She centralised decision-making power in her office to increase efficiency and fired tens of thousands of workers to cut costs.

In 2000, the company added chairman to her list of titles, making her the first woman to hold all three top posts - president, CEO and chairman - at a major computer company.

Ms Fiorina, one of the few women to head a Fortune 500 company, bet her career on the success of the Compaq tie-up.

"I think the company’s success will be my legacy," she said in October 2002. "The company’s failure will be my failure, with all the predictable consequences of that."

Ms Fiorina had recently been forced to play down reports that the H-P board was considering shifting her day-to-day duties to other executives. She called the report "speculation" and said her relationship with the board was "excellent".

Today, announcing her decision to stand down, she said: "While I regret the board and I have differences about how to execute H-P’s strategy, I respect their decision."

Ms Fiorina will be replaced temporarily by Robert Wayman, H-P's chief financial officer, the company said.

Patricia Dunn, an H-P director who was named non-executive chairman of the board said: "We thank Carly for her significant leadership over the past six years as we look forward to accelerating execution of the company’s strategy."

The company said that the search for a replacement chief executive would start immediately.

H-P announced last month that it would combine its printing unit with its PC division and that Vyomesh Joshi would take control of the combined business, a move many interpreted as establishing Mr Joshi as a likely successor to Ms Fiorina.

Ann Livermore, presently head of H-P's corporate computing division is also considered a key contender for the role.

Read Hewlett-Packard's statement here

Hewlett-Packard at a glance

REVENUES

Fiscal year 2004

$24.2bn Printers
$15.2bn Enterprise storage and servers
$13.8bn Services
$0.9bn Software
$24.6bn PCs
$1.9bn Financial services
$0.5bn Corporate investments

OPERATING EARNINGS

$3.8bn Printers
$0.2bn Enterprise storage and servers
$1.3bn Services
$0.2bn PCs
$0.1bn Financial services

LOSSES

-$0.1bn Software
-$0.2bn Corporate investments

Source: Fortune magazine

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