The judgment was made at the High Court this week in relation to a case of an 18-year-old care leaver whose "pathway plan" review was carried out by his personal adviser and not a social worker.
Mr Justice Parker said that this was unlawful as personal advisers are employed as an intermediary between social workers and care leavers.
He added that the personal adviser can be involved in the review of the plan, but must not carry out the review itself. This is the role of a social worker, he ruled.
The aim of the pathway plan is to ensure looked-after children are supported when they have left care until the age of 21, or 24 if they are still in education. This plan has to be reviewed every six months.
The 18-year-old’s solicitor, Oliver Studdert, said: "This judgment makes clear that social services cannot cease to be involved with children leaving care once they reach 18. The role of the personal adviser should always be to work with the young person and to play a negotiating role with social services on their behalf. All too frequently a personal adviser also plays the role of social worker."
A Lambeth Council spokesperson said: "We take this case extremely seriously and are reviewing our procedures in light of the High Court judgement. We will ensure that where personal advisers are involved in the review of pathway plans, this will be under the supervision of a qualified social worker."
