Firstly, is it possible for the Labour Party, less than twenty years old at the time, to have become the party in power at the start of the Great War? If so, what effect would this have had on the course and outcome of the war?
Would the UK have switched parties during the war? If the UK started with a Liberal government as in OTL, could Labour have gotten in at the switch, rather than the Conservatives?
How would a Labour government have dealt with the peace negotiations? Would the treaty still have planted the seeds of WWII?