Here is a scheme I have been thinking about if we are required to return to school. 

Subject “Clusters”

Actual numbers will, of course, be different and we may rely on many teachers teaching non-specialist subjects. and limit optional subject.

Assuming 90ish students per year we can split each year into 3-4 groups. And thus the school into 21-28 groups. This will end up with 3-4 “Subject Cluster”

Students only study 4 Subjects with the same number of teachers. They only rotate between those subjects for 3 weeks. Therefore teachers and students are only seeing the same people. e.g 15 hours of Maths, 15 of Geography, 15 of Biology, 15 of Art, 15, over 3 weeks. We would also try to keep this in the same 3-4 adjacent rooms

If you school does sets, The 4 classes per subject can also be divided into 4 levels of ability, lower, middle, higher abilities and lastly online. Many parents will opt to not return their children to school immediately. So we will have only a fraction of the student body on site at any one time

At the end, there is a week off. Students go home and do large homework task. This gives time for any symptoms to show up and the whole student/teacher cluster can then be isolated.

After they return the students move onto another cluster  English, Drama, Chemistry, Computer Science, over few weeks and repeat

If the week off is also rotated you can have a situation where only 75% classes are running at any one time.

Combine this with 1/4 classes being online and you can have around 56.25% of students on site.

We can also split up the day into four 1 hour 15 minute lessons running from roughly 8am-2pm. Since each cluster can have an independent time table we can stagger the clusters over a range of start times between 7am and 9am. End times between 1 pm and 3 pm.

Convoluted but if we have to return this will limit the number of contacts.