"I know we should adopt a positive attitude and we've more chance of being ran over by a bus but excuse me if I am getting slightly weary and troubled by it by now..."

There's no reason to get even the slightest bit bothered. There's nutters everywhere who do meaningless acts of stupidity everyday. There's way too much hype about all this.

I wouldn't elevate these rogue elements above their status or get flustered otherwise they've acheived their objectives. My attitude is to laugh at them, as they blew them selves up for no good reason. They've not changed my attitude to travelling in London or returing to living in Leeds in the near future.