Programme Management plays a crucial role in successfully executing a group of related projects which together achieve a common purpose in support of the strategic aims of the business. Effective monitoring and controlling activities in the context of a programme are essential to ensure adherence to budget and schedules. Forecasting cost estimate at completion is a fundamental aspect when managing a group of projects in a coordinated way. The thesis focuses on the development and implementation of statistical linear predictive models to enhance cost estimation accuracy and precision in comparison to the most widely used index-based methods, thereby enabling more informed decision-making, proactive cost control, and practical implementation guidance.