Why Italy concentrated its battle fleet at Taranto

Why did Italy concentrate so much of its battle fleet at Taranto?

Taranto offered the best base for eastern-Mediterranean operations and seemed safely protected inside Italy, assumptions the British raid overturned.

Taranto was the Regia Marina's best base for operations in the eastern Mediterranean. Its position inside the heel of Italy made it appear protected from an enemy carrier force bold enough to enter the Gulf of Taranto. The later British cruiser movement through the Strait of Otranto magnified the shock because Italian reports imagined the force had penetrated farther into the Adriatic than it really had. Concentration joined operational reach to a harbour believed to be a sanctuary. The raid exposed how a sound basing choice can become a dangerous single point of failure when an opponent defeats its assumptions.