So most of us have probably heard this claim. Is there actually any truth to it, as in, if the Germans had not gone trough Belgium, the UK would have remained on the sidelines of the conflict?
The violation of the neutrality of Belgium was the direct cause for Britain to declare war on Germany.
Would the UK have remained on the sidelines? Difficult to say but the UK hadn't bothered to become involved in the previous war between Germany and France in 1870. However the UK's position of neutrality in Europe had changed since then and they were in a triple entente alliance with France and Russia since 1907.
My prediction: the UK would have stayed out of the war, providing logistical support and blockading the German navy until it was clear France would lose unless they entered the war.