If Italy joined the Central Powers at sea

Could Italy and Austria-Hungary have cut the Mediterranean if Italy entered the war with the Central Powers?

They might achieve a short-term division, but Britain would build and concentrate overwhelming strength while defending Gibraltar and contesting Malta, Alexandria, and Suez.

The combined Italian and Austro-Hungarian fleets could create a serious short-term crisis and neutralize much of the French position in the Mediterranean. Britain would have to hold Gibraltar with mines, submarines, torpedo craft, destroyers, and surviving French support while maintaining the Grand Fleet elsewhere. Regaining the initiative might require a two- or three-to-one capital-ship advantage, renewed construction, and possibly a struggle over Malta. Alexandria and the Suez Canal would be more exposed because they lay farther from Britain's secure western entrance. Even then, von Spee would need timely news and a usable route before an eastern approach could change his fate.