FTSE posts biggest ever one-day points fall

* FTSE 100 down 391 points; biggest ever one-day points fall

* Banks rocked by fresh uncertainty

* Miners, oils knocked by falling crude, metals prices

(Click on [ID:nL6259237] for more on financial crisis)

By Jon Hopkins

LONDON, Oct 6 (Reuters) - Britain's leading share index recorded its biggest ever one-day points fall on Monday with banking and commodity stocks taking a battering as the fallout from financial crisis once again overwhelmed global markets. The FTSE 100 .FTSE ended 391.1 points lower at 4,589.2, down 7.8 percent, the third biggest percentage decline, taking the index back to levels not seen for over four years.

No blue chip stock ended in positive territory.

"Another Monday, another banking crisis. Just when the market thinks it has found a base level, there's another jolt to the system." said Manoj Ladwa, senior trader at ETX Capital.

" Black Mondays used to be a once-a-decade event, now they're coming along more regularly than a London bus," Ladwa added.

Banks were among the biggest blue chip fallers with Barclays (BARC.L: Quote, Profile, Research, Stock Buzz), Royal Bank of Scotland (RBS.L: Quote, Profile, Research, Stock Buzz) and HBOS (HBOS.L: Quote, Profile, Research, Stock Buzz) down between 14.7 and 20.5 percent.

The UK finance minister Alastair Darling told parliament in the afternoon that a Banking Bill will be introduced Tuesday to build on special powers the UK government took in February.

The bill will also give the Bank of England a statutory role to maintain financial stability, the UK finance minister added.

The European Union pledged to protect people's savings and maintain financial stability as more governments followed Germany's lead in offering blanket deposit guarantees to savers as German authorities clinched a deal to rescue lender Hypo Real Estate (HRXG.DE: Quote, Profile, Research, Stock Buzz) at the second time of asking.

Investors were also concerned whether a $700 billion bailout package agreed last week from the United States would be big enough to prevent a global recession.

U.S.stocks dropped back heavily, with the Dow .DJI losing almost 5 percent, falling below the 10,000 level for the first time since Oct 2004.