BHP Billiton on Wednesday said full-year pre-tax profits halved to $11.6bn as the global economic downturn triggered a collapse in demand and the prices of commodities sold by the Anglo-Australian miner fell by up to 90 per cent.

However, the mining group said it was encouraged by the brighter outlook emerging from developing markets in recent months, particularly in China and India, where there was evidence customers were re-stocking commodities.