In its latest effort to stop oil gushing into the Gulf of Mexico, BP is trying to guide a mile-long tube into the breached well.

BP technicians are gingerly moving joysticks to guide deep-sea robots and thread the 6in-wide tube with a rubber stopper into the 21in pipe spewing oil from the ocean floor.

A week ago, BP attempted to capture the leak with a 100-ton containment box, but that effort was abandoned when ice crystals encrusted the box.

The company also received word that federal regulators had approved spraying chemical dispersants beneath the sea, a contentious development because it has
never been done underwater.

Traditionally used on the ocean surface, chemical dispersants act like a detergent to break the oil into small globules, which allows it to disperse more quickly into the water
or air before currents can wash it ashore. Louisiana officials claim BP
and the US Environmental Protection Agency ignored their concerns about
how the chemicals may harm the sea floor.

Meanwhile, more than three weeks since the oil rig explosion that killed 11 workers and set off the disastrous spill, President Barack Obama attacked oil drillers
and his own administration as he ordered extra scrutiny of drilling
permits.

He condemned a "ridiculous spectacle" of oil executives shifting blame in congressional hearings and denounced a "cosy relationship" between the companies and the federal government.