It feels like catch 22. If numbers fall dramatically from tomorrow, then great, no need to close schools, tier 4 is working. If they don't fall tomorrow, then look, its 10 days since school closed, cases haven't fallen so clearly schools aren't the problem.
Or it could be the other way, cases fall tomorrow- shut schools work, let's do that, cases not fall tomorrow - we are in a crisis, schools need to shut.
Could go either way with this government and the figures will be used to prop up what they have decided to do. (Which they will communicate to schools at the last moment, then have a go that they weren't prepared.)