SINGAPORE, Oct 10 (Reuters) - London Metal Exchange nickel futures tumbled 10 percent on Friday to their lowest in just under three years as worries about a global economic meltdown sent investors running from industrial raw materials.

By 0358 GMT, London Metal exchange nickel <MNI3=LX> fell $1,250 to $12,150 a tonne, after dipping as low at $12,050, its weakest since November 2005.

LME copper <MCU3=LX> dropped 9 percent and Shanghai metals slumped by their downside limits after plunging equity markets fanned fears the world is heading for a deep and lasting economic downturn. (Reporting by Nick Trevethan; Editing by Kim Coghill)