London's FTSE 100 index of leading shares experienced some wild swings on Friday - at one point it gained and lost 300 points in a matter of minutes.

Stockbroker Tony Craze of Goy Harris Cartwright told BBC News that he understood the problem was caused by a city trader who pressed the wrong button when doing a deal.

"I'm told somebody lost about �100m ($155m) out there today."

He said he thought the trader involved worked at one of the big American banks.

Volatile day

Markets on both sides of the Atlantic wobbled on Friday because of continuing worries about corporate profits, the US economy and a possible war with Iraq.

I think we still have a lot of problems

James Volk DA Davidson

Another reason for the volatility was that a large number of futures contracts were due to expire - and that always affects share prices.

In New York shares managed to hold onto some of their gains after three days of heavy falls.

An encouraging statement from the wireless technology company Qualcomm helped cheer investors.

More problems

James Volk, managing director of equity trading at DA Davidson said: "I think it's more of a technical bounce than anything else."

"I still see no change in the outlook - no growth in the economy, which means there is not going to be growth in earnings.

"I think we still have a lot of problems," he added.

The Dow Jones index of leading shares ended up 44 points at 7,986.

London's FTSE 100 index closed 47 points higher at 3,860.

Germany's Dax index fell below 3,000 for the first time since January 1997 although by the time the markets closed it had recovered and was 58 points higher at 3,066.

But the Paris Cac fell 36 points to 2,891.