(Reuters) - London's FTSE 100 dropped on Monday, as economists slashed their expectations for the global economy this year and a raft of UK-based companies laid out expected hits to profit, cuts in spending and the potential for trouble with rising debt.The blue-chip index fell 4.8% by 0813 GMT - sinking back into the red after a two-day bounce due to the extraordinary stimulus unveiled by governments and central banks in the UK and beyond last week.Troubled fashion retailer Ted Baker Plc ..