By Dominic Lau

LONDON (Reuters) - Britain's top share index ended down 2.3 percent on Friday, registering its biggest weekly fall in six years, as banks and commodity stocks fell on global economic worries after the U.S. jobless rate jumped last month.

Vodafone was the top-weighted loser, down 4.5 percent after top mobile phone maker Nokia warned the soft global economy, tough competition and a weak handset portfolio would hit its market share in the third quarter. Nokia shares tumbled nearly 10 percent.

The FTSE 100 ended down 121.4 points at 5,240.7 for a weekly loss of 7 percent -- the biggest such fall since July 2002. The UK benchmark is down nearly 19 percent so far this year.

"It's surprising how things can change in a few days. Earlier in the week there was talk of the inflation threat receding with crude oil prices falling. Markets were looking a little bit rosy. We were thinking there might be a rally towards the end of the year," said Tim Whitehead, head of portfolio services at Redmayne-Bentley.

"Now things have turned on their heads ... We are in a bear market and these are the bear rallies that we should expect. The best we can hope is for the market to continue to trade in a range between 5,200 and 5,600 which it has been doing in the last few months."

European shares also finished the day sharply lower, while U.S. stocks were down.

Banks were among the standout losers on the FTSE 100, with comments from European Central Bank President Jean-Claude Trichet on Thursday adding to fears about the ability of the financial sector to weather the slowdown.

HSBC, Barclays, Royal Bank of Scotland, HBOS, Lloyds TSB and Standard Chartered shed between 1.2 and 3.6 percent.