Since President Volodymyr Zelensky prioritised the technology, Ukraine has invested hundreds of millions of dollars into long-range drones, capable of searching out and striking distant targets. Half a dozen firms now make them. America’s concerns have varied, from a rise in the oil price to the prospect of an uncontrollable tit-for-tat in which Ukraine could end up the loser. Fears of the latter rose in late March, when Russia inflicted millions of dollars of damage on Ukraine’s energy infrastructure. Ukraine is ignoring US warnings to end drone operations inside Russia. Its superdrones can reach targets as far away as Siberia. Is a global crisis around the corner ?

