The DFE define a set of policies they regard as stautory here: https://www.gov.uk/government/publications/statutory-policies-for-schools
Note that some policies are only applicable to some types of school (PRU, Sixth Form, Free School, Private school, Academy etc)
For Academies, the academies financial handbook also makes reference to the following policies:
- Accounting policies
- Investment policy
- Competitive tendering policy
- Acceptance of Gifts, Hospitality etc
In addition, at a local authority school your local authority may have requirements for certain finance policies to be in place