The National Curriculum is organized into blocks of years called key stages. There are four key stages as well as an Early Years Foundation Stage (EYFS).
key stage 1 = infants –5 -7 years old
key stage 2 = juniors – 7 – 11 years old
key stage 3 = lower secondary school – 11 – 14 years old
key stage 4 = GCSE – 14 – 16 years old