Global mining giant BHP Billiton posted its worst profits for more than a decade after being hit by plunging commodity prices amid the slowdown in China's economy.

The world's biggest miner saw annual net profits crash 86 per cent to $1.9 billion (£1.2bn) while profits on an underlying basis more than halved, down 52 per cent to $6.4bn (£4.1bn) - lower than expected and the worst performance for more than 10 years.

BHP, run by Scottish born chief executive Andrew Mackenzie, said it had cut its forecasts for steel demand in China and warned the country's slowing economy would lead to further market volatility.

Miners across the sector have been hammered by slowing demand from China as the world's second largest economy has faltered.

Sharp falls from miners have seen global markets tumble, with around £74bn wiped off the value of blue chips in London alone yesterday in a grim session now dubbed 'Black Monday'.

But BHP's shares were six per cent higher today despite its worse-than-expected full-year results as markets staged a bounce back.

Fellow miner Antofagasta also booked share gains in the market rebound despite its own set of grim results. It reported underlying earnings for the first half down 48.6 per cent to $562m (£356m).

Anglo-Australian group BHP, which is the world's largest miner by market value, said commodity prices had fallen in its year to the end of June and were "notably lower" so far in its new financial year.

Mr Mackenzie said: "In the short term we expect ongoing economic reforms in China to contribute to periods of market volatility.

"We expect near-term volatility to continue as the authorities press ahead with reform in a cautious but sustained manner as they seek to improve the efficiency of capital allocation in the economy while maintaining support for employment.

"However, our robust longer-term outlook for China remains intact as the economy transitions."

BHP said it would cut costs, lowering its target for capital spending in the next financial year from $9bn (£5.7bn) to $8.5bn (£5.4bn).

It also offered some cheer as the group's debt mountain reduced by five per cent to $24.4bn (£15.4bn), while it added its commitment to shareholder dividend payments remained unchanged despite the profits hit, increasing the full-year payout by two per cent to 124 cents a share.