They have become a familiar sight in the skies above parts of Russia: long-range enemy drones, buzzing their way to another target. In the biggest Ukrainian onslaught inside Russian territory since Vladimir Putin’s full-scale invasion two years ago, Ukraine has in recent weeks carried out a series of attacks on Russian oil refineries and ports. On Tuesday, it hit a refinery and drone factory in the industrial region of Tatarstan – more than 800 miles from the border.

The Ukrainian spy agency behind these drone strikes has its eyes on another target: the 12-mile long Kerch bridge connecting occupied Crimea with Russia. Senior officials from Ukraine’s HUR military intelligence service indicate it is plotting a third attempt on the bridge, after two previous attempts to blow it up, claiming its destruction is “inevitable”.