When I was at primary in the 1970/80s 36 was the norm in my school, and no TAs.
In my area the primary schools are all full to bursting because of immigrants, but not from places forrin' but refugees from London looking for a nice (or maybe naice) place to raise children that's still in commuting distance from the city.
We need more schools, proper schools not free schools, to deal with the problem but I can't see it happening.