Ian is accredited by ITAA/EATA as a Teaching and Supervising Transactional Analyst. He is also a UKCP Registered Psychotherapist and a Master Practitioner in Neuro-Linguistic Programming (NLP). Ian is co-author of TA Today (Lifespace, 1987), the world-standard basic text on TA, and of Personality Adaptations (Lifespace, 2002). He has contributed books on TA to three widely-read series published by Sage Publications: TA Counselling in Action (3rd ed., 2007), Eric Berne (1992) and Developing TA Counselling (1996). In 1998, Ian was awarded the EATA Gold Medal "for outstanding services to TA in Europe". He has been a practising TA psychotherapist for over 25 years, and has presented TA trainings worldwide.

Adrienne is a Teaching and Supervising Transactional Analyst, a UKCP Registered Psychotherapist, and a Master Practitioner in NLP. She has been practising as a psychotherapist for over 25 years, and has been centrally involved in the development of TA in Britain from its earliest beginnings. Originally trained by the late Professor John Allaway, Adrienne is a founder member and past Chair of the UK's Institute of Transactional Analysis (ITA). She is the current past President of the European Association of TA (EATA) and is also on the Board of the European Association for Psychotherapy (EAP).

Mark is a Teaching and Supervising Transactional Analyst and UKCP Registered Psychotherapist, and holds the European Certificate in Psychotherapy. He is also qualified in integrative counselling and is a COSCA accredited diploma trainer. He has served as Editor for the ITA News since 2002 and was a former Council secretary for the ITA. Mark is an international expert for the Training Accreditation Council of the European Association for Psychotherapy, and is a member of the UK’s ITA Training Standards Committee. Mark has written numerous articles and book chapters on various aspects of TA psychotherapy. He is also a trainer on a number of other psychotherapy courses, including an MA programme (also validated by Middlesex University) in Integrative Psychotherapy for the Athens Synthesis Centre.