Why is it impossible to find appropriate clothing for little girls in the UK?

Why is it that when I look in high street shops for nice clothes for a 5 year old....that I am faced with black leggings, biker boots and animal print tunics teamed with thin belts? Since when did what is ok for a 16 year old to wear become ok for a 5 year old? I just looked at NEXT online...their age groups go from 3 to 16! So we are meant to dress a 3 year old in the same thing a 16 year old wears? The kids on the site are in all these poses. that look weird for kids....not y exactly but definitely grown up....it annoys me! Why cant I find a nice dress for a CHILD?