In 2001, before the term “e-portfolio” was common parlance there was a perceived need to enable teachers in training to save, store, present and archive their electronically-based work so that it could be assessed by tutors. A number of alternatives were considered but none met the criteria determined by the tutors and mentors at the time. A Teacher Training Agency (TTA) Grant was used to design and implement an online system for trainee teachers to save evidence of their activities called Electronic Portfolio System (EPS). Initially, the system was to be used for those training to be ICT teachers but it was made open to all subject areas. Over the years, its use and value has changed and, through the support of the Teacher Development Agency for schools (TDA), the system will continue to develop. The principles underpinning the original and developing features of the system were established before the coding began but can be summarised in this single phrase: protected, easy, open, secure and free access to locally stored folders The features of the system have grown organically because of technology changes and by tutors and mentors identifying affordances. This presentation will identify the principles and how they guide the development process. It will give an opportunity to elucidate the next stages in e-portfolio developments.