Fig. 2

CONSORT diagram for the internal pilot phase. ¹Eleven schools were actually recruited in the pilot, but two of the recruited schools were due to merge in the 2018/2019 academic year (single-sex schools merged into two mixed sex schools) and therefore are considered as one school for the purposes of the trial (i.e. they have been randomised as one school). ²Year 7 (age 11–12) and year 8 (age 12–13) were approached in schools in England and Wales, and S1 (age 11–12) and S2 (age 12–13) were approached in schools in Scotland