BP begins 'top kill' bid to stem flow

BP says it has begun pumping mud into a breached Gulf of Mexico oil well to try to stem the flow of oil caused by a rig explosion last month.

If the oil flow is successfully capped, engineers will follow up with cement to seal the well permanently.

There is a risk a weak spot in the blowout preventer that sits on top of the well could breach under the pressure, causing a brand new leak at the site 50 miles (80km) off the Louisiana coast.