Could Britain have stayed out of World War I?

Was it realistic for Britain to avoid or delay entering the First World War?

Yes, if Germany respected Belgian neutrality and stayed away from the Channel; otherwise British intervention became politically likely.

British neutrality requires Germany to respect Belgium and avoid naval actions in the Channel that would bring in the Royal Navy. An attack directly across the Franco-German frontier would instead encounter heavy French defenses, reducing the prospect of a quick victory. If Italy also stayed neutral, France and Russia would face Germany and Austria-Hungary in a war that might end through negotiation. Senior British ministers opposed intervention, and Lloyd George was prepared to challenge entry into what he regarded as an offensive war. Britain could still favor France through merchant shipping, preferential loans, and controls on exports such as Welsh coal. German interference with that trade could create another route into war, so the scenario depends on continuing German restraint. The invasion of Belgium and Germany's declaration of war supplied the political trigger for overwhelming support for British intervention.