When I was at Anfield, my first task each morning was to create a "substitution list". Aided by computer software, one of the Deputy Head Teachers and I found cover for teachers who were absent from illness.
If we were lucky, there would only be a few teachers needing cover. In the event of a teacher being absent for more than three days or a teacher away on a course, we phoned a supply teacher agency to get outside help. Up to £100,000 of the school's budget was swallowed up paying for agency staff to cover each year.
Many of the agency supply staff were good teachers who merely needed work set by a Head of Department to get on and teach the classes. Some would even bring their own work. Even still, the lessons would often be "fill in material" not related to the normal lesson the children would be given by their regular teacher.
As schools in the UK open for the Spring term, the worry is about staff shortages due to Covid. Clearly, the staff shortages that schools will face also affect the agencies so the option to recruit supply staff to help out will be limited.
Schools have therefore been advised by ministers to start preparing for COVID staff shortages by merging classes into larger groups and considering "flexible" teaching options.
In his open letter to school leaders, the Education Secretary said this involves "utilising all your available teaching and non-teaching workforce to maximise on-site education for as many pupils as possible while you flexibly deliver provision either on-site or remotely to some pupils".
However, he added that this "should only be on a short-term measure".
"I urge you to do everything in your power to protect face-to-face learning for our children and young people and am confident that you will of course make every endeavour to do so," he said.
There were occasions where it was necessary to combine groups at Anfield and it was always one of Deputy Heads or a senior member of staff who would look after them*. Normal classroom teachers would likely have refused and we would not have asked support staff to take on such a task on their own.
Since there were no classrooms large enough for a double or treble class, the senior member of staff would take them to the Assembly Hall and put on a video using the large screen and projector that we had installed for lunch times. It was hardly worthwhile learning, more child minding as the children watched episodes of the Simpsons.
Combined groups will almost certainly be of different abilities and possibly of different ages so it will be difficult to provide any meaningful education to them. The logistics of organising these arrangements will be complicated.
* The Head Teacher never volunteered to help out, he always claimed to have something more important to get on with. We never asked him.