Success.....For the Moment

Now comes the big question, well casing integrity.

BP has successfully placed a new cap over the leaking Gulf of Mexico oil well.

The success was revealed on murky live pictures from an underwater camera and broadcast on BP's website.

They show the "Top Hat 10" device hovering and then lowering completely over the well that had been gushing a mile (1,600 meters) beneath the surface.

The valve has been designed to be a much tighter fit than its predecessor, so as to completely contain the oil.

Once it is screwed into place, BP plans to perform an "integrity test" lasting between six and 48 hours. The US government and BP are due to decide by Thursday whether the valve can stay in place to seal the well shut.