During his two-day trip to Estonia, Prince William visited some of the 900 British troops in this multinational force, including soldiers of the Mercian regiment of which the prince is colonel-in-chief.
He saw forces at the military training grounds at Tapa Camp – part of Operation Cabrit in which a British Army Brigade is held at readiness to secure Nato’s “collective security and defence” in this vulnerable Baltic region.
This is what deterrence to Russia looks like on the ground – and the base shows how much the balance of power can shift.
Before Estonia regained its independence in 1991, this had been a base for Soviet air defences, with MIG fighter planes poised to take on the West.
Now the positions are reversed, with Estonian troops and their Nato allies training here to prevent a Russian incursion.
As well as riding in a Challenger 2 tank, the prince saw a Warrior armoured vehicle, a French Griffon fighting vehicle, a multiple launch rocket system, a Trojan vehicle for clearing obstacles and the prince drove an Archer mobile artillery system.