Teacher time taken by specialist support staff
It will come as no comfort to teachers, parents and politicians protesting about non-teaching staff giving youngsters instruction in sport and the arts that something similar is long established south of the border.
Outdoor education and enterprise are just some of the lessons which may not be delivered by traditional teachers there.
Some want no truck with the principle in Scotland arguing that instruction is likely to be superficial. There's concern untrained teachers may for example address for the most part the most extrovert children in the class or even lack the skills to engage the majority of the class.
Potentially there could be bored or ignored children.
Others argue the injection of new blood from the outside world especially young blood isn't the worst thing that can happen to a school. More than one teacher goes straight into teacher training after completing their own education which limits the experiences they can draw on.
Some teachers don't believe they received substantial training in sport and the arts so may not be totally against someone else taking over those subjects.
But for teaching unions the concern is that the introduction to schools of less well paid instructors makes it more difficult to uphold teachers' pay, conditions and status.
You can watch a discussion on this topic from Sunday's Politics Show Scotland (around 35 minutes in)