Gordon Brown has called on energy firms to slash fuel bills as gas and oil costs fall.

With winter approaching, the Prime Minister urged suppliers to pass on their savings from declining wholesale prices to hard-pressed consumers.

It follows his insistence this week that falling oil prices should be reflected at the petrol pumps.

Writing in The People newspaper, the premier said: "Now that global oil and gas prices are falling, we will demand that energy companies pass on these cuts to their customers as price reductions as soon as possible."

Pressure has been building on garages and energy suppliers to cut prices as the cost of oil has fallen to less than half its 147 dollar-a-barrel high in July. This has helped wholesale gas prices to slump by about 20% from its record levels in the summer.

The economy is widely held to be on the brink of a recession, while the downturn is spreading throughout the globe.

US president George Bush is set to host a summit of world leaders to discuss the global response to the financial crisis.

He is holding talks at Camp David with French president Nicolas Sarkozy, who is holding the rotating presidency of the European Union, and European Commission president Jose Manuel Barroso.

Earlier, Mr Brown warned that the financial crisis had exposed the "weaknesses" of unfettered capitalism.

While maintaining that he was pro-business, the Prime Minister said the relationship between governments and the markets was being studied anew and that financial systems must reflect the values of "fairness, stewardship and co-operation" cherished by families and communities".