UK Terror Alert Critical

The current terrorist threat level in Britain is now at its highest: Critical. So what else is new? As someone who lives in Greater London, I can't see any difference between Critical and Severe, except that the Home Secretary appears on TV to tell us all to be vigilant. I travelled on the Underground to Oxford Street Station on Friday afternoon, despite the bomb scares in the morning, and the biggest delay was caused by some wally falling on the line at Liverpool Street Station. I think these threat levels are too abstract to have any meaning. So I've devised my own. Feel free to copy my graphic.