Belgian neutrality and Britain's room to maneuver

If France invaded Belgium instead of Germany, would Britain fight France, join the Central Powers, or ignore the treaty obligation?

Britain might break with the Entente without becoming Germany's ally, because Belgium was protected by a guarantee rather than a direct alliance.

Belgium had a guarantee of independence rather than a full British alliance, leaving Britain several possible responses. Britain could plausibly stay out militarily, monitor both armies, and insist that Belgium's independence be restored after the war. It might also sell weapons without joining either coalition, preserving leverage while avoiding an immediate alliance reversal. Pre-1914 treaty obligations did not map neatly onto automatic naval commitments.