If that fails, BP will have to try more elaborate measures. It is making preparations to drill another well nearby and thereby relieve pressure on the one that is leaking.

In response to anti-fracking protests, France has slapped a moratorium on the practice; in Britain, activists for Frack Off, a pressure group, have shut down drill sites.

This pressure must be under control, and we control it by means of the mud which we circulate down the drill pipe.