During 2012/13, academics from the Department of Education, University of Oxford were commissioned by CfBT to conduct an independent evaluation of the CfBT Brunei English teaching programme. This report describes the main findings from a research project that studied the role of CfBT Education Trust in supporting improved English language teaching and outcomes in Brunei Darussalam. A case study approach was used to explore the development of the bilingual education system in Brunei Darussalam and the Ministry of Education's (MoE) collaboration with CfBT in facilitating this since 1984. The study sought to document the various processes of change and improvement within the Bruneian education system, in particular those related to the teaching of English as an additional language in the bilingual system and the involvement of CfBT as an external education provider and change agent. The research adopted a multi-method case study approach that collected and analysed data from a cross-section of perspectives and a range of data sources. These included interviews with key stakeholders of the system (senior officers from the MoE, CfBT management and project leaders, English language teachers from both CfBT and Brunei, school senior management and students) and school visits. Documents related to CfBT's engagement in education initiatives, teaching and learning materials, Bruneian government policy, project reports, previous research, student attainment data and academic literature were also analysed to provide additional perspectives and a wider evidence base. After an Introduction, presented are the Methodology; Key Findings and Analysis; Discussion and Conclusions. Appended to the report are: (1) Timelines; (2) CLIL resources; (3) Interview schedule examples; (4) Coding template with example interview excerpt; and (5) Code definitions and key. [This report was written with Catherine Walter. For the research briefing, see ED546808; For the summary report, see ED546819.]