Energy giant BP's latest desperate attempt to siphon gushing oil from a broken pipe in the Gulf of Mexico has failed as the toxic slick grows to 10 miles long.

As BP struggled to contain the environmental disaster, scientists have found enormous oil plumes lurking beneath the surface of the water, including one as large as 10 miles long, three miles wide and 300ft thick.

The discovery suggests that the leak could be 'substantially worse' than estimates given previously by BP and the government.

Growing concern: This satellite image shows a clearly-defined oil slick in the Gulf of Mexico. Scientists have discovered huge plumes of oil lurking under the surface of the water