In reference to the article “Does NLP work? Is it the basis of Derren Brown’s “mind control” act?”, perhaps I can help, having studied psychology, and NLP, and (to a much lesser extent) Derren Brown.
A more helpful definition of NLP might be "an attempt to discover what, if any, were the commonalities of three “master psychotherapists” - Fritz Perls, Virginia Satir, and Milton Erickson - who, when personally practicing, were capable of inducing significant changes in patients in a single session. Bandler and Grinder then attempted to “distill” the elements in common - in theory the “effective core” as opposed to the overlying (and conflicting) belief systems of the individual therapists.
This definition highlights the oddity of asking whether NLP “works” - as psychology students study the techniques and practice of all three of these psychotherapists (among others) - and certainly no one makes claims that their techniques “do not work.” If one has studied NLP and watches videos of Perls, Satir, or Erickson conducting therapy, it is easy to identify techniques used in NLP that are used by these therapists - who are still presented today as appropriate learning models in graduate psychology classes.
Additionally, NLP specifically adopted an explicit, “well, if something doesn’t work, do something else” strategy from Perls and Satir, who both practiced that style of therapy - thus confounding the question of what, exactly one would “empirically study” to determine whether NLP did or did not “work”. Neither Fritz Perls, Virginia Satir, Milton Erickson, or the founders of NLP believed that any particular techniques would invariably “work” with every single patient.
Most people seem to be unbothered by the fact that some individual psychologists are effective, while some are not effective, quite regardless of the “branch” or overall “theory” of psychology that they adopt in order to understand the reasons behind their actions. Empirically, there is little to support the idea that any particular theory of psychology is more effective than any other - as none is capable of producing adherents who are uniformly more effective than any other theory. NLP differs mainly in failing to adopt an explanatory theory at all, preferring to say, essentially, “these tools seem to have proven effective, we make no claims as to a unifying theory behind their effectiveness.”
As for Derren Brown and NLP, the “apparently erroneous belief that Brown achieves some of his effects via NLP” stems from watching Derren Brown implement recognizable NLP techniques on his shows. While there is certainly a question as to whether the recognizable NLP techniques that he implements are a major source of his success, or whether the success is attributable to tricks of mentalism is another question - but in as much as the practitioners of any art tend to be able to identify it when practiced (just as the speakers of a language recognize it when it is used) it is relatively silly of Brown to claim that NLP is not part of what he does in his performances.
The question raised by those who recognize NLP techniques when they are used is, of course, if the NLP techniques were not an effective part of what Brown does, why would he faithfully reproduce them, when the actions performed would have no meaning whatsoever to, and would be missed by, the vast majority of the population. Thus, since the NLP techniques have no particular “mystical” appearance to the normal viewer, then their use by Brown would appear to point to efficacy, rather than showmanship or camouflage.