I don't see how anyone could think it was anything other than complete fakery after the ludicrous straightjacket on the railway line scene.
Apart from the obvious point that neither DB nor C4 would ever subject someone to that kind of physical risk or mental trauma, the multiple camera angles - from mysteriously invisible braodcast quality cameras - gave it away.
Almost all of the 'real' people involved appeared to be acting - badly.
The mother was the only one who I thought at all plausible.
As other critics here have pointed out, it was little more than a badly acted, poorly produced work of fiction.
Had it been presented as pure fiction I doubt it would ever have made it into production, let alone be broadcast.
DB's last three 'specials' have been unfathomably bad.
The lottery one did at least present a bit of a puzzle, albeit one that was solved withing minutes on this and other message boarRAB, but the casino fiasco and this one were just very, very, poor TV.
I've always taken DB's psychobabble/NTL flim-flam for the misdirection it is, but in the past he did at least make some effort to use it as subtle and (almost) believable disguise for what were always basically conjuring tricks and slick post-production work.