British army is 80-90% short of drones as military exercise aims to build on European defence strategy

Deep in Charing Cross underground station, in the disused terminus of the Jubilee line, a secret Nato command bunker has this week been discreetly at work. Dozens of mostly British soldiers were engaged in a war game defending Estonia from a Russian invasion in 2030, unbeknownst to commuters and tourists bustling above.

The secret chambers are behind two sets of normally locked, metal double doors. A red glow at the bottom of the escalator beyond is the first sign of troops below; next are mocked up newspaper covers pasted over ageing adverts. A British Nato force has deployed to Estonia they blare, in response to a Russian massing of troops on the border.