Energy giant BP made a new attempt to siphon gushing oil from an offshore well as political pressure and public outrage increased over the company’s slow progress at stopping environmental disaster.

London-based BP Plc admitted on Saturday that its latest attempt to contain the spill had failed but a top executive expressed optimism that the tricky undersea effort to redirect the flow of oil would be operational overnight.

The latest fix involves guiding undersea robots to insert a small tube into a 21-inch (53-cm) pipe, known as a riser, to funnel the oil to a ship at the surface.