English in Action (EIA) is a nine-year (2008-2017) language education programme aspiring to improve the communicative English language skills of 25 million people in Bangladesh. This large-scale international development project aims to contribute to the economic growth of the country by providing communicative English language as a tool for better access to the world economy. EIA is working collaboratively to implement the programme with its partners, BMB Mott MacDonald, BBC Media Action (previously BBC World Service Trust), The Open University, UK and two national non-governmental organisations, the Underprivileged Children's Educational Programme (UCEP) and Friends in Village Development Bangladesh (FIVDB). This presentation will illustrate how the Open University is using low-cost alphanumeric mobile phones within a work-based programme of professional development with 12,500 teachers over the next three years. Drawing on robust pilot studies, internal and external research monitoring and evaluation, we outline how mobile phones have transformed our work-based teacher professional development model. The mobile phones not only complement teachers' reflective professional development, but also provide them with more than 700 audio flies—stored on micro SD cards—directly aligned with the national textbook, English for Today. These audio files provide both teachers and students with unprecedented access to hear near-native English language examples of textbook lessons, activities and readings without relying on Internet access. Participation in the programme has already significantly increased the number of teachers and students who are able to communicate in English to levels that enable them to participate more fully in economic and social activities and opportunities. In the presentation we will demonstrate how the low-cost Nokia mobile phone (C1-01) and accompanying project materials work to support English teachers in engaging in new student-centred communicative teaching and learning practices that are also socially inclusive. Additionally, we illustrate how the mobile phone delivers teacher professional development videos that explain, model and encourage English teachers to try out, reflect on and document their new communicative language teaching practices.