This photograph was taken at Nedderton School (thank you to cccdisp for identifying the location). There is also a photograph in this collection of the adults at this event.
In addition to the very patriotic costumes including that wonderful army uniform, there seem to be two or three "Wee Willy Winkies" (pyjamas and a candle stick), two flower girls, a nurse, gypsies, a milkman and others. One little boy at the front seems to have missed out on a costume - he looks a bit upset. Someone in the back row looks as if they would rather have done without their costume, which I think may be "Old Mother Riley".