Waterborne threat
Wasn't there a similar topic to this on here, a few years back but as a part of a UAV debate? Or was it on E-Goat or ARRSE, where someone pointed out with a quote on 'further down the food chain' stuff gets passed down. The nightmarish scenario of a container ship / pleasure boat / sailing up the Thames (or any other waterway for that matter) and the bad guys letting loose a fair amount of MAVs with IED.