Under section 20 a local authority must accommodate a child in need who appears to need it because there is no one with parental responsibility for them, they are lost or abandoned, or the person caring for them can't provide suitable accommodation or care. It can also accommodate a child where that would safeguard or promote their welfare.
It is often called voluntary accommodation, because it works with the agreement of the parents. Anyone with parental responsibility can remove the child at any time (section 20(8)), unless someone else holds a child arrangements order or special guardianship order. There is no court order and the local authority doesn't gain parental responsibility.
A child accommodated for more than 24 hours is a looked-after child (section 22). They get the same entitlements as any other looked-after child: a care plan, a PEP, an IRO and support from the virtual school. Most unaccompanied asylum-seeking children are looked after under section 20.
Section 20 or a care order? KCSIE 2026 paragraph 236 asks schools to know a looked-after child's legal status: voluntary arrangement or interim or full care order. It affects who can consent to things like trips and who school should contact. Ask the child's social worker if you're not sure.