Its forces have trained hard for just such an engagement, as well as working on improvements to civil defence, supply lines, planning and public relations.

BBC: Hamas ready for bitter urban battle

The bottom line is that Mr Osborne has difficult times ahead, but the eurozone and the OBR have given him some very good lines of defence.

BBC: Bad news for Labour in OBR

And there were further lines of defence.

BBC: Back to whose reality?

South Korea's defence minister, Lee Sang-hee, said North Korea's navy threatened its maritime supply lines.

ECONOMIST: Asia's navies