R (G) v Southwark LBC  UKHL 26
Section 20(1) entails a series of judgments, helpfully set out by Ward LJ in R (A) v Croydon LBC  EWCA Civ 1445, at para 75. I take that list and apply it to this case.
• Is the applicant a child?...
• Is the applicant a child in need? This will often require a careful assessment. In this case it is common ground that A is a child in need essentially because he is homeless.
• Is he within the local authority’s area?
• Does he appear to the local authority to require accommodation?
• Is that need the result of:
• There being no person who has parental responsibility for him; for example, where his parents were unmarried, his father does not have parental responsibility, and his mother has died without appointing a guardian for him;
• His being lost or having been abandoned; or
• The person who has been caring for him being prevented from providing him with suitable accommodation or care.
• What are the child’s wishes and feeling regarding the provision of accommodation for him? … It follows, therefore, that every item in the list had been assessed in A’s favour, that the duty had arisen and that the authority were not entitled to ‘side-step’ that duty by giving the accommodation a different label.
See also: Provision of Accommodation for 16 & 17 year old young people who may be homeless and / or require accommodation: Guidance to children’s services authorities and local housing authorities about their duties under Part 3 of the Children Act 1989 and Part 7 of the Housing Act 1996 to secure or provide accommodation for homeless 16 and 17 year old young people – issued April 2010 SCSF -
2.23 There can be no doubt that where a young person requires accommodation as a result of one of the factors set out in section 20(1)(a) to (c) or section 20(3) then that young person will be in need and must be provided with accommodation. As a result of being accommodated the young person will become looked after and the local authority will owe them the duties that are owed to all looked after children, set out in sections 22 & 23 and once they cease to be looked after, the duties that are owed to care leavers under that Act.