The Alliance for Youth Justice briefing ‘Adultifying Youth Custody: Learning lessons on transition to adulthood from the use of youth custody for young adults’ explores how the Government’s decision to temporarily raise the age young people transfer from the children’s secure estate to the adult secure estate from 18 to 19  resulted in a 253% increase in the number of over 18s in the child estate. The briefing highlights the lost opportunity for systemic reform during this time and warns of the long-term risk of blurring the boundaries between youth and adult justice systems.