* FTSE 100 drops 7.2 percent

* Commodity stocks slump on mounting recession fears

* Banks fall led by HSBC, StanChart (For more on the financial turmoil, click on [nCRISIS])

By Jon Hopkins

LONDON, Oct 15 (Reuters) - Britain's top share index lost 7.2 percent on Wednesday, ending a two-day rally, as commodity stocks slumped amid growing fears of global recession.

The FTSE 100 .FTSE ended down 314.6 points at 4,079.6, erasing a big chunk of the near 12 percent rebound seen in the previous two sessions after plummeting 21 percent last week, its second worst weekly fall on record.

"It's all or nothing with the FTSE at the moment, with yet another large one-day movement," said Tim Hughes, Head of Sales Trading at IG Index.

"The comedown after the euphoria of the multi-billion pound bail-outs earlier this week seemed inevitable, although a sharp rise in the latest UK unemployment figures hasn't helped matters," he added.

Miners were the biggest losers, as base metal prices fell and after Rio Tinto (RIO.L: Quote, Profile, Research) warned of slowing Chinese demand for commodities and signalled a possible delay in plans to sell $10 billion in assets.