Foreign nationals ,means anyone that isn't British either by birth or marriage.
Oh that's not enough to not be "one of them" any more
This year for the first year school census is asking for numbers on DUAL nationals, and nationals born outside of the uk
so it's not enough to be legitimately British any more, you have to be pure british to not count in the "other" numbers!
It was all rubbish when they said "we welcome people who integrate". So people integrated, got their residencey, and then got (and paid £1k for) citizenship thorugh naturalisation, and did everything they were told they should do if they wanted to be the "right" kind of welcome foreigner…… and now they're being counted as "other" anyway!
Oh and FWIW citizenship through marraige only exists on paper now, in practice it doesn't give any advantage in the naturalisation process, so having a british family doesn't really qualify you as not "other" now either
And because they now want to count dual citizens as "other" (even though they are FULL british citizens, just also full citizens elsewhere too), then it's not enough to be born and raised here to british parents, if you have a foreign grandparent through whom you have dual citizenship, you're "other" too!