Speculation was mounting today over the future of BP boss Tony Hayward as its staff prepared to return to the storm-hit Gulf of Mexico.

A pivotal moment in the Gulf oil crisis hit an unexpected snag when officials announced they needed more time before they could begin choking off the geyser of crude at the bottom of the sea.

BP robots have attached a new, tighter-fitting cap on top of the gushing Gulf of Mexico oil leak, raising hopes that the flow of crude polluting the water can be stopped for the first time in nearly three months.