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The Five Case Model is the HM Treasury best practice approach to business case development, mandated across much of the UK public sector for all significant spending proposals.

It considers five key questions:

  • is there strategic fit and a strong case for change?

  • has a wide range of options been considered and can we demonstrate value for money?

  • is the service delivery commercially viable and what does the deal(s) look like?

  • is the proposal affordable and where are the funds coming from?

  • what is the plan for successful delivery of the proposal?

Joseph Lowe, Head of the UK Treasury Economics Branch describes the Five Case Model, which is the best practice standard for business case development across the UK public sector

For large, complex projects where there might be several procurements and a formal procurement process has to be followed, an iterative approach is used as shown opposite.  This level of detail included in the business case analysis to answer the five key questions proportionately should be proportionate to the scale of investment and risk involved. 

The Five Case Model best practice guidance is available from the HM Treasury website.

The HM Treasury Green Book is available from the HM Treasury website.

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