I researched this latly as wondered how it vairies from steiner.
its is difference.
at nursery /foundation level i think now the british currcuculum is learning through play so distinctions not obvious.
but at primary year 1+
it means no testing
grading
but teaching same subjects as other schools
maths, science. english, history, geography, ,music re.
like state primary without the pressure.
dont know what it be like at high school-would they take qualifications.
but have read that montessori primary kids dont end up behind.
they catch up with their peers and have ended up going into selective senior schools.
from what i can tell its very relaxed atmosphere than normal primary or prep, small classes, more homly environment the montessori classrooms look fab. think in some ways prolongs childhood as the play element is not lost , they dont have huge pressures and focus heavily on the arts.
www.dailymail.co.uk/news/article-407528/Children-Montessori-schools-better-educated.html- hate to quote daily mail its bit old but good study and the deprived primary in manchester had some success with it.