BP's 'static kill' to seal Macondo well

BP will this week start "static kill" operations designed to put an end to the biggest oil leak in US history.

After delays caused by Tropical Storm Bonnie, final preparations to reinforce the relief well drilled near the broken Macondo well in the Gulf of Mexico are going ahead.

If all goes according to plan, either today or tomorrow BP will begin to pump heavy "mud" down into the well, to force the oil spill back into the reservoir. Once the mud has done its job, the bottom of the well can be plugged with concrete, forming a permanent cap.

The Macondo well was temporarily capped in the middle of July, stopping a three month-long spill that has polluted vast tracts of ocean and swathes of the US coast.

Last week BP's chief executive, Tony Hayward, stepped down – to be replaced by US colleague Bob Dudley. Hayward said he had been "demonised and vilified" in the US, after the explosion on the Deepwater Horizon rig at Macondo in April killed 11 people and unleashed the slick.