e P8 to P9 2019–20 2021–22 2023–24 Under 10 16 9 3 -80% -71% Age 10 2 3 4 -40% 52% Age 11 9 3 3 -88% 2% Age 12 19 19 9 -84% -53% Age 13 41 69 32 -76% -53% Age 14 176 171 168 -47% -2% Age 15 438 522 587 -13% 13% Age 16 1,401 1,606 2,005 28% 25% Age 17 2,668 3,345 4,382 97% 31% 53 The consequent increase in the proportion of children in care in the 16+ age group who are UAS is shown in Figure 20. Figure 20: Number of UAS children aged 16+ in care as a proportion of all children in care aged 16+ Source: SP9 respondents. The numbers are extrapolated from 123 local authority responses based on the proportion of the England population. DCSs expressed a strong commitment to supporting UAS children in SP9 interviews, and those most closely engaged with this issue shared proactive thinking and planning in shaping appropriate responses. Many DCSs discussed the ongoing demands of providing appropriate placements and support for UAS children and adolescents who need trauma- informed support and care. The absence of national planning and support to enable an effective and sustainable asylum system was a source of real concern. 4.6 UAS care leavers The large proportion of older UAS children leads to care leaver numbers rapidly expanding. Many UAS adolescents will have been in care only weeks or months before turning 18; in one local authority there were twice as many former UAS care leavers aged 18–25 years as there were UAS children in care aged under 18. SP9 data demonstrate both the great increase in the total number of care leavers since 2017–18 and the proportion who are former UAS children increasing from about 12% in 2017–28 to about 18% in 2023–24. 12,878 14,977 15,277 15,699 3,786 4,069 4,951 6,387 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 2015–16 2019–20 2021–22 2023–24 P