Young People and the WW1 Centenary

My year 9 class are presently revising for their end of year exam.  They will be asked two iGCSE-style questions on the origins of the First World War.  So what should today's generation know about the causes of this war that they will (hopefully) be reading, seeing, hearing and talking about in the next five years?  After a recent Twitter spat about this topic with Professor Gary Sheffield, I have been reflecting on my answer to this question.
If  there is just one thing I would like to have achieved in the last nineteen years of teaching, it is that the students in my lessons learn that the 1914-1918 conflict was not just caused by the Germans.  I am  sure that many previous generations of British school children have been taught just this, that WW1 was started by those "nasty old Germans."  (This view must have been particularly prevalent after 1945 and a war that is more easy to blame some people from Germany for.)
However the causes of WW1 are not so clear cut for me and this is one of the many things that makes  WW1 more fascinating and complex for me.  I do not believe that Britain went to war in 1914 to protect liberty, certainly not Britain's liberty.  My fundamental view is that ALL countries that took part in this dreadful conflict were, in part, responsible for its start and yes, that includes us, or rather Britain.  It also includes Germany who were certainly no angels in the summer crisis and if it were not for the Schlieffen Plan, an Eastern European war might not have spread westwards.
Despite what others think (!), I will always teach that the war started for a variety of different and complex reasons which involved to a lesser or greater extent all the belligerents.  So I will teach about Serbian officials' complicity in the assassination of Franz Ferdinand, Austria's desire to smash Serbia's growing strength before it was too late, Russia's inability to mobilise purely on just the Austrian border, France's desire for 'une revanche' and yes, the Kaiser's blank cheque to Franz Josef and the Prussian military's desire for war.
However I will also teach that Britain was also partly responsible. Britain was not obliged to fight as part of the Entente Cordiale of 1904 or defend Russia in the 1907 treaty. Britain went to war in 1914 because Britain wanted to go to war.  The German invasion of Belgium was a big part of this and we all know about the 1839 treaty.  However just as Fritz Fischer's 'Griff nach der Weltmacht' blamed Germany, there is also Dangerfield's 'The Strange Death of Liberal England' which claims Britain decided to involve itself to escape the domestic problems of militant Suffragettes, striking miners, railwaymen and dockers as well as the 'Irish problem'.  I also feel Britain went to war because Britain is a European power and wished to prevent a continent economically and industrially dominated by Germany.  However I always stress to my students what are facts and what are my opinions.
So good luck in your exam gentlemen and remember, the First World War was not just caused by the Germans.  It was caused by them and many other European countries, including the one you are writing your exam in!  That's not just my opinion, that's a fact!