New economy shares were bathed in red for most of the day after a raft of profit warnings on both sides of the Atlantic led to another wave of negative sentiment.
And if the poor corporate news was not enough, crucial unemployment figures released in the US this afternoon came in worse than expected.
Although the FTSE-100 Index closed just 20.3 points down at 5601.5, London analysts are worried about further falls next week.
In London, investors were on the back foot from the start after software group Autonomy warned revenues for the first quarter would fall below expectations.
It blamed the impact of the US slowdown on European businesses, which were now putting off big orders with the firm.
Autonomy closed the session down a massive 43%, or 245p at 325p and it took a host of tech stocks on the FTSE-100 - the index it left in the last quarterly reshuffle - down with it.
The falls were given further impetus when US markets opened, and fell, on the back of profit warnings from three tech stocks of their own.
Chip designer Arm Holdings topped the Footsie fallers board, dropping 11%, or 34p to 256p ahead of its own first quarter results next Wednesday.
Software groups Misys and Sage were also off, falling 42p and 15½p to 415p and 234½p respectively.
Computer service firm CMG dropped 42½p to 430½p while its rival Logica tumbled 78p to 802p.