You can’t miss the vast banner emblazoned on the high-rise building overlooking central Vilnius. It reads: PUTIN, THE HAGUE IS WAITING FOR YOU. Not one to mince their words, the Lithuanians. And neither are the Latvians or Estonians. In the face of an increasingly menacing Kremlin, the Baltic states – on Nato’s front line against Russian aggression – display an in-your-face bravado, which nevertheless overlays a palpable unease about the future.