In the US they have these to give off a warning of anything from a poor water source to a nuclear attack and I would like to see something like this used in the UK even if the chance is small. It could also be used for many other things like giving a warning to everyone if an attack happens like what happened in France where there was live fire on the streets or even what happened in Australia with people being taken hostage, I feel it would be very useful if we would have something to warn as many people as possible of things like this as it could save a lot of lives.