The Department has a substantial legacy technology estate, in part because it has not prioritised the investment needed to keep it up to date.63 Defence Digital, the organisation responsible for leading on the digital strategy, estimates it will cost £11.7 billion over 10 years to remediate just its own legacy systems.64 We asked the Department whether it was more cost effective to fix its legacy systems gradually, or simply to start afresh with a different approach. The Department explained that from now on it will ensure its programmes set aside money to keep systems up to date for life and comply with the rules of its future architecture. The Department said it is taking a risk-based approach to 55 Q 23; C&AG’s Report para 19 56 Q 11 57 Q 10 58 Q 23 59 Q 43 60 Q 67 61 Q 93; C&AG’s Report, paras 3.5–3.6 62 Qq 93–94; C&AG’s Report, para 3.6 63 Q 45 64 Q 47; C&AG’s Report, para 11 The Defence digital strategy 15 upgrading the legacy systems it already has and considers factors such as vulnerability to cyber-attack and the value of the data. However, the Department told us it will take time for this approach to result in a healthier, more current technology estate.65 Using data for advantage