Following the introduction of the No 3 Investment Department on January 1st 1967, a separate style of passbook was issued for this type of savings account. Reflecting the higher rate of interest to be paid on this 'Special Investment' account, a superior style of passbook was used, as illustrated below. The passbook had a more substantial feel that those used for the No 1 and No 2 Departments, having a stiff cover instead of a flexible one.