This article reports on the outcomes from the "e-scape Primary Scientific and Technological Understanding Assessment Project" (2009-2010), which aimed to support primary teachers in developing valid portfolio-based tasks to assess pupils' scientific and technological enquiry skills at age 11. This was part of the wider "e-scape" project (2003-present), which has developed an innovative controlled alternative to design & technology and science public assessment at age 16. Teachers from eight primary schools were trained in the use of an online task-authoring tool to develop and trial assessment activities based on current classroom work. To compile their e-portfolios of assessment evidence, pupils used netbook devices, which afford multi-modal responses (text, drawing, photo, audio, video, spreadsheet) whilst leaving space on pupils' tables for practical investigations. Once the pupil e-portfolios had been uploaded to the secure e-scape website, teachers assessed them using a "comparative judgement" approach to produce a rank order with a high reliability coefficient. Participant teachers recognised the strength of the e-scape approach in terms of facilitating and managing pupils' responses to assessment tasks in the classroom, which they successfully adapted to suit primary pedagogy. In particular, the benefits of scaffolding complex assessment tasks through the step-wise e-scape process in the authoring tool represented for some of the teachers a pedagogically significant development in terms of their planning.