After frenzied activity, by Monday this week the $1 billion facility had been brought back from the brink and restored to near-horizontal trim at its normal displacement of around 130,000 tonnes.

A week earlier, at 8.30am local time on 11 July, a startled world and an even more startled BP were informed by a passing ship that the immense semi-submersible Thunder Horse was wallowing in the water at a list approaching 30 degrees.

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