OB,
We are not supposed to know that....besides why should it matter they have a very expensive piece of ballast and all they can do is throw up two up raised digits at the enemy when they run out of missiles.
Problems
In 2001, it was announced that the RAF would not use the aircraft's internal cannon. This is not due to any perceived inadequacy in the cannon, but instead reflected a need to save money by removing gun support costs, ammunition stocks, training costs, etc. The gun was also deemed unnecessary since the missile armament was believed to be adequate in the Typhoon's fighter role. [8] However, because removal of the cannon would affect the aircraft's flight characteristics, requiring modification of the aircraft's flight software the RAF decided that all of its Typhoons would be fitted with the cannon but that it would not be used or supported. The service argued that this would save money by reducing the requirement for ground equipment, removing training costs and avoiding the fatigue effects of firing the cannon. The RAF maintains the option to activate the cannons at very short notice should operational requirements change. [9]