Taken in isolation, they could just about be explained away as coincidences – freak accidents, one-off attacks, unfortunate infrastructure failures. The DHL cargo plane that crashed on Monday as it approached Vilnius airport. The recent bomb scares that have hobbled London, from Euston Square and Gatwick Airport to the US Embassy. The drones spotted circling near US Air Force bases in the UK. The explosion at a weapons manufacturing facility in Wales in April.
