Here is some info on a second airspace violation over the UK as reported by Sky News:

http://news.sky.com/skynews/article/0,,30100-1280809,00.html

                   It is the first time the £60m Eurofighter has been scrambled on a genuine alert since it took over defence                    of Britain's airspace in June. The MoD said in a statement: "RAF Typhoons from Numbers 3(F) and XI                              Squadrons launched to shadow a Russian Bear-H aircraft over the North Atlantic Ocean on Friday 17                              August 2007."

It is really difficult to imagine the logic behind this type of action. It is easy, however, to understand the reason why Russia is able to take such actions: Russia has a huge nuclear arsenal and with such WMD capabilities it is very easy to push other nations around. While that may seem like a simplistic answer that's because the answer really is that simple. Granted, Russia is hardly an insane regime and isn't going to launch a nuclear war on a whim. It is an emboldened nation and it is trying to send the message that a powerful Russia is back.