Shares in telecoms group Cable and Wireless (C&W) have fallen 11% after it issued a profit warning and said its chief executive was to step down.
More changes are in store for the telecoms group
C&W said its underlying earnings for the 2006/7 financial year were expected to be no higher than for 2005/6.
It added that chief Francesco Caio will leave in April after three years at the helm as part of a revamp at the firm.
C&W is to split its operations into two subsidiaries - international and UK. It said the move would lead to job losses.
However, the UK's second largest telecoms provider said it was too early to say how many jobs might be cut as a result of the reorganisation.
Shares in the group closed 12.25 pence, or 11%, lower at 102.25p.
C&W said that Mr Caio would be stepping down at the start of the new financial year as the post of group chief executive was being axed as part of the restructuring.
The firm said that the revamp and a drop in costs would boost profits for the current year but leave earnings for 2006/7 under pressure.
As a result, it expects underlying earnings for 2007 - including its £674m Energis acquisition but excluding internet provider Bulldog - to be no higher than for the current financial year.
Analysts said the warning - C&W's second in four months - could see almost £100m wiped off current earnings forecasts for the group in 2006/7 of around £250m.
"Today's reorganisation marks a significant step in the development of C&W," chairman Richard Lapthorne said.
He added that the changes would leave the group in good shape for the future, despite facing "extremely challenging" conditions in the short term.
Mr Caio added that in the UK, the longer term focus of the business would be "success through scale, access and internet provider capability".
The latest shake-up at the firm has triggered speculation that it could be about to be broken up - with the demerger of one of its two subsidiaries - but the chairman denied it was ready for such a move.
"You have got to be a pretty strong and well-run company to actually envisage demerger and we are not quite there. In fact we're a long way from there," Mr Lapthorne said.
The telecoms group has suffered a turbulent five years and has lost a quarter of its workforce in that time. Its share price has slumped from a high of £15 in early 2000.
But three months later it revealed half-year profits had fallen by almost a quarter amid "tough" market conditions and increased competition.