I have been directed (by email) to teach both my class and another colleague's class at the same time, to cover for her sickness absence. This is long term absence and the first instance is next week. She will likely be absent until summer.
Both classes are small because they are extremely challenging, which means I will have a class of 30 very, very difficult kids. Obviously no useful work will get done (my class is fairly well trained but will not cope with this).
Can anyone link to guidance which supports me saying no? Any assistance appreciated.