The arrival of the US M1A1 Abrams tanks in Ukraine was hailed as a turning point in the war. Coming in at roughly $10 million a unit, the Nato stalwart was supposed to provide the armoured fist that would punch through the Russian lines. But tactics evolve quickly in warfare, and Russia’s use of surveillance and hunter-killer drones has led to heavy casualties for Ukraine’s tank fleets. This is alarming for NATO. If Russia has found critical vulnerabilities in our armour, our borders are beginni