Sophie, 14, won her battle at Ricksmansworth School, Hertfordshire. Teachers and governors decided to allow girls to cover up with a change in uniform policy last month.
She now exorts others with a message that will resonate in the harsher Scottish climate: "There are still many schools where girls cannot wear trousers as part of their uniform. I think this is rally unfair as girls get cold too. You always have to worry when you bend down to tie your shoe laces or when it's windy.
"Also, we constantly have to shave our legs if we wear skirts! I'm sick of girls being discriminated against in this way."
In February, Professor Claire Hales challenged a skirt-only policy at Wickham Comprehensive in Gateshead on behalf of her daughter Jo, backed by the Equal Opportunities Commission.
The potential costs of the case forced the school to settle out of court and its revised dress code allows boys to wear dresses.