Unseen and underhand: Putin’s hidden hybrid war is trying to break Europe’s heart

From Norwegian pipelines to French ocean floor cables, vital infrastructure is vulnerable to Russian attacks designed to destabilise Europe

Nato planners have always worried about the Storskog border crossing in Finnmark, where Arctic Norway comes face to face with the cold reality of Russia. In Soviet times, the 121-mile frontier was a potential flashpoint. The Red Banner Northern Fleet's nuclear-armed submarines are still based at nearby Murmansk, on the freezing Barents Sea.

Reasons to worry afresh about the border are multiplying following Vladimir Putin's invasion of Ukraine. Norwegian police recently arrested several Russians, equipped with drones and cameras, who were showing unusual interest in oil and gas installations. Some of the suspected spies entered via Storskog.