Schoolgirl stockings - An interesting photograph

The mid to late 60s saw the miniskirt become almost universal at a time when stockings were still worn by many women and girls.  Schools reacted with horror to ever-rising hemlines and I  can remember well one female teacher saying with disgust that "stocking tops could be seen as girls walked up stairs".  We lads reacted with pleasure and erections!!  Schools set out rules about skirt length.   In this picture girls are checking their skirt lengths while one girl unwittingly reveals that she is wearing stockings.  It takes me back; how I loved the sight under a school skirt of a suspender strap pulling at the top of a stocking.