The financial director of embattled British telecoms group Marconi, Mr John Mayo, who was due to become its chief executive, resigned late last night, a group spokesman said.
The resignation comes amid a collapse of Marconi shares following a warning on Wednesday that profits would halve this year and another 4,000 jobs would be axed in addition to 3,000 already cut in 2001.
Following his resignation, Mr Mayo said: "Marconi is a great company going through difficult times that are not of its own making.
"The entire workforce faces immediate short term challenges and it is inevitable that sacrifices will have to be made."
Shares nosedived 54 per cent on Thursday following the announcement of Marconi's collapse, and there was no reprieve yesterday
By the close of trading, its shares were down 7 per cent or 8 pence at 104.5 pence.
Mr Mayo had been due to succeed Lord Simpson as chief executive, who would have become chairman.
Present chairman Sir Roger Hurn confirmed he would remain in the post, and Lord Simpson would carry on as chief executive.
Marconi is not alone in suffering from the slowdown in capital spending that has been prompted by the global economic slowdown.
In recent months, big names like Cisco, Nokia, Ericsson, Nortel and Alcatel have all alerted investors that the downturn will eat large holes in their bottom lines this year.
Marconi traced its own problems back to last year's feverish auctions of third generation mobile telephony licences.
Mr Mayo on Wednesday predicted a turnaround for Marconi next year, when he said networks "will be running so hot they'll fall over".
Telecoms analysts continued to slash their forecasts for the group, which said on Wednesday its profits would halve and 4,000 jobs would go as it succumbed to the global technology slowdown.
In two days of hectic trade, Marconi, one of the world's top seven suppliers to the cash-strapped telecoms industry, has lost almost £4 billion ($5.5 billion) - over half its market value - and has tumbled to the bottom of the FTSE 100.
