Britain's most senior sailor, First Sea Lord, Adm. Jonathon Band, said the underwater crash posed no risk to the safety of the submarines' nuclear reactors and nuclear missiles.

That argues for a mature politician, such as David Miliband or Mr Balls, rather than a promising novice.

Yet sovereignty was the great unmentionable at his meeting with the British foreign secretary, David Miliband, and Gibraltar's chief minister, Peter Caruana.