Commodities prices are tumbling from historic highs, as investors reverse bullish bets on everything from corn to copper and oil in the latest sign of recession fears gripping financial markets.

Brent crude dropped below $100 a barrel on Wednesday for the first time since April, leaving it 29 per cent below its recent peak. Other markets have also faced severe falls, with the broad S&P GSCI agricultural prices index down 28 per cent since its all-time high in mid-May and a London Metal Exchange benchmark tracking half a dozen industrial metals losing a third of its value since peaking in March.

Such steep declines come as major central banks turn the screws on monetary policy, jacking up interest rates in a bid to curb scorching inflation. Investors are fearful that higher borrowing costs will derail the global economy after rapid price growth triggered a cost of living crisis.