19 The government's reforms to central buying have not been well managed. Although CCS customers can save money by using CCS deals, we would have expected more savings would have been delivered if CCS had been set on a sounder footing. As a result, central government has not yet achieved value for money from its central buying. When it created CCS the Cabinet Office relied significantly on its mandate to require departments to use CCS. However, it severely underestimated the difficulty of implementing joint buying across government. Without a sound overarching business case or a detailed implementation plan, it is not surprising that CCS rapidly ran into difficulties and soon had to reset its plans. It is particularly disappointing that the Cabinet Office has not tracked net costs and benefits. Because of this, it is not possible to show that CCS has achieved more than departments would otherwise have achieved by buying common goods and services themselves.
20 However, the strategic argument for joint buying remains strong. For central government to achieve value for money from its common goods and services, it needs to finish the centralisation it began in 2014. The events of the past two years have shown that, in practice, joint buying needs both a mandate and goodwill from departments. CCS is making changes to its operations which it expects to improve services in the future. CCS needs to demonstrate that this has worked in order for departments to want to use it.