I refer the hon. Member to the oral statement made by my right hon. Friend the Secretary of State for Defence on 21 January 2008, Official Report, column 1225.
The extent of the details retained on any individual depends upon what stage of the recruit selection process an applicant either opted out or was found to be not suitable. In all cases this would include all personal details as requested on the armed forces application form (AFCO form 4). For those whose applications are progressed, details of medical and selection process results and possibly security clearance results, may also be retained.