So we have another U-turn, and we have another fudged policy that puts enormous pressure on headteachers and schools: face masks will be mandatory in certain areas in secondary schools during periods of local lockdown, but everywhere else the decision will left down to a headteacher.

The problems with this approach - and the guidance that goes with it - are multiple. Here are the key concerns.

1. By shifting responsibility to headteachers, the government has thrown heads to the court of parents, who will likely have a range of very different ideas about masks. It will be almost impossible to keep every parent happy, and their anger will be directed at the head, not the government. The lack of a clear policy based on scientific evidence leaves heads extremely vulnerable. 
2. The government has left it incredibly vague as to when heads may wish to use masks. The head could mandate masks if they believe social distancing is impossible, or they could mandate them because it will make some parents feel more confident in sending their children to school. They have said classroom wear is not necessary, but as for everywhere else? It’s up to heads. As Nick Brook, deputy general secretary at the NAHT school leaders’ union, tweeted - heads are not epidemiologists, the call of when and how a face mask should be worn should not be down to schools. 

   Clarity of advice not ‘discretion’ was needed. Headteachers are not epidemiologists. If public health experts deem face masks necessary to the safety of secondary pupils and staff then government should say so, clearly. @NAHTnews https://t.co/Xlip1Kzl3z

   - Nick Brook (@nick_brook) August 26, 2020

   
    
3. The guidance states that hands have to be washed before you put a mask on and after you take it off. How, as a school, do you get the students to a place to wash their hands to put the masks on, when that will likely involve movement through areas where a mask is apparently needed? And how do you get a thousand students all washing their hands twice in every transition without it taking an incredibly long time?
4. The guidance also states that masks have to be stored in sealable plastic bags - and be ditched if they become damp. It is optimistic at best to expect all students to keep track of a plastic bag for the entire time they are in school, and what does ‘damp’ actually mean? After trekking to lunch and back, or for outside breaktimes, possibly in rain or damp air, and then the mask being put in a sealed plastic bag in a warm backpack… it would be a surprise if that mask was ever not damp. So how many masks will a child need per day?
5. Schools will have to buy a supply of masks for those that cannot afford them. For some schools, the cost will be enormous, and that is even if they can get hold of some masks. Due to lost masks or adhering to the guidelines, schools may need multiple masks per child. Indeed, the general guidance on masks is that you wash them after use, so how many masks will each student need across a week if they need multiple per day? And how much extra cost is this going to put on schools, with no sign of extra funds from government?
6. The government says students will need to be educated in the right way to wear a mask. So who delivers that training, and how often does it need to be repeated? Moreover, who polices it? Correct mask-wearing may make a huge difference in a lab where wear is closely monitored, but in a school? How can correct wear be monitored, and if it is not, what impact will the mask actually have?
7. Will schools need to mandate certain kinds of mask? You can now buy elaborate designs and very expensive options - how do schools prevent pressure being put on families to spend big for social capital in school? And again, how do you police it?
8. On the issue of behaviour, the government is clear that “No-one should be excluded from education on the grounds that they are not wearing a face covering” - which means that whether a school mandates it or not, individuals can opt-out and schools cannot do anything about it. So while giving schools power, that power is blunt. And again, explaining that to pro-mask parents is going to be tricky.

As professor Trish Greenhalgh has told Tes, masks are a sensible approach to the current situation. Even if they make only a small difference, it’s better than no difference.

But schools need a sensible policy on masks from the government to make them effective, one that is properly financed and that communicates the detail. Unfortunately, they don’t have it.