Since HA (Iraq) in the Supreme Court, the "unduly harsh" question in deportation appeals has to be answered for the actual child in the actual family, without measuring them against some notional child who could be expected to cope. That sounds obvious. In practice it changed what evidence wins these appeals, because a generalised statement that separation harms children no longer does the work. The tribunal needs to know about this child.
What social work evidence adds
A social worker's job, done properly, is precisely the individual picture. What does this child's day actually look like, and where is the appellant in it? What does the school say, and the GP? How does this child respond when the parent leaves the room, and what has already happened to them in their short life that bears on what a permanent separation would do? Both scenarios the tribunal must consider, the child going and the child staying, need that treatment, separately, because they are different questions with different answers.
What it cannot do
A social work report cannot decide the appeal, and a report that argues the case instead of evidencing it will be read for exactly what it is. It cannot make findings about disputed events; that is the tribunal's job. And it cannot manufacture harshness where the evidence shows resilience. An expert who reports that a child would cope, where that is what the evidence shows, is doing the appellant a service in the only currency that matters, which is credibility.
Why the family court connection matters
Many deportation families have family court history: previous proceedings, social services involvement, assessments. That material cuts both ways and it will be known to the Home Office. An expert who works in the family courts can read that record fluently, put it to the family, and deal with it in the report before the presenting officer deals with it in cross-examination. The alternative, a report that ignores the record, has been publicly criticised by the Upper Tribunal, and the criticism followed the expert, not the solicitor.
The practical point
If you are running an Exception 2 case, commission the child evidence early, send everything, and instruct against the legal test. The difference between a report that recites the family's account and one that has tested it is usually the difference between "little weight" and evidence the determination quotes.