my view that the default position was to do as you were told.

I do not think the Lefties and Socialists of that time would accept that slur.

I earlier quoted the Socialist Party of Belgium in 1914 who issued a statement to say that their members were defending themselves against 'militarist barbarism' and fighting for liberty and democracy.

The leading left wing paper in Britain then was The Manchester Guardian.

"The Manchester Guardian had been very strongly opposed to war, and frankly isolationist. No one was more insistent on the need to keep out of a European war than the paper's chief leader writer and deputy editor, CE Montague. But when war was declared, he was so appalled by German perfidy that he enlisted, aged 47, dying his grey hair to conceal his age."
http://www.theguardian.com/news/2014/dec/09/-sp-myth-of-the-good-war