https://www.nhs.uk/Video/Pages/how-to-wash-hands.aspx

In the information sent from Surrey Council to schools they advise to prevent the spread -

• pupils, students, staff and visitors should wash their hands:
  • before leaving home
  • on arrival at school
  • after using the toilet
  • after breaks and sporting activities
  • before food preparation
  • before eating any food, including snacks
  • before leaving school