In this special bank holiday episode, we’re taking a break from looking at the US-Iran war and focusing instead on tanks. Since it first appeared on the Somme battlefield, the Tank has dominated and defined modern warfare. It has been such a successful concept that its distinctive silhouette - two tracks, a turret and a gun - has barely changed in a hundred years. But can it survive in the century of the drone? Or will the venerable tank go the way of the armoured knight before it? Hamish de