To ask the Secretary of State for Defence how many Joint Strike Fighters he intends to order for the Royal Navy. 
The Joint Strike Fighter (JSF) has been selected to meet our Future Joint Combat Aircraft (FJCA) requirement, to replace the current Harrier aircraft of Joint Force Harrier (JHF). FJCA will be flown by both Royal Navy and Royal Air Force personnel, from the new carriers and land bases. While no final decisions have yet been taken, our planning assumption is based on 150 of the Short Take Off and Vertical Landing (STOVL) variant of JSF being acquired to meet the FJCA Requirement.
To ask the Secretary of State for Defence (1) if he will take measures to ensure that weapons stocks procured before the Joint Strike Fighter enters UK service will be able to operate efficiently on the JSF; (2) if it is his policy that measures will be taken to ensure that UK air-launched weapons stocks can more fully inter-operate with US aircraft and vice versa; (3) if he will make a statement on the extent to which the UK's air launched weapons stocks can inter-operate with US aircraft, and vice versa, in current operations. 
The interoperability of air launched weapons with our allies is one of a number of factors considered when procuring new systems.The United Kingdom has a number of air launched weapons which could be inter-operable with United States aircraft and vice versa, such as Maverick, for example. However it is not usual practice to share stocks as notionally common weapons often have different national sub-systems, such as fuzes. Changes to these would therefore be required before the weapons could be used by other nations' aircraft.During the acquisition of air launched weapons due consideration is given to their potential to operate effectively from JSF if they are likely to be in use when JSF is in service.