But I think there is a low probability that will play out, not least as we have learnt from history.

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Mr Morrison said the company had been pushing ahead with those changes, which had not been fully implemented at the time of the Deepwater Horizon accident, and introducing new systems and technologies as a result of the lessons it had learnt from its investigation of the disaster.

CNN: BP claims it now leads the way on safety

But as Israel learnt in Lebanon in 2006, this is far from easy.

ECONOMIST: Israel's war in Gaza

But, though Mr Blair is happy to use the past as a rhetorical device, he does not seem to have learnt from it.

ECONOMIST: British society

I've learnt from that and now I look on every defeat as a learning experience.

BBC: Danny Crates' running tips

He likes to tell people how, in his first job as a Mars management trainee, he learnt that the best way of sweeping up Maltesers from the factory floor was first to step on them.

ECONOMIST: Royal Mail