This research report investigates the role of line managers and leaders in employee development and retention, focusing on Marks and Spencer as a case study. It examines the conceptual framework of talent development and retention, the specific roles played by line managers and leaders, and the challenges faced in implementing retention strategies. The literature review covers performance management, learning and development support, and motivation, highlighting the talent management model used by Marks and Spencer, which includes planning, attracting, developing, retaining, and transitioning talent. Challenges such as lack of employee engagement, unfair wages, lack of appreciation, and a changing workforce are also explored, concluding that effective talent retention strategies are crucial for boosting employee engagement, performance, and overall organizational success. The report employs a deductive research approach and survey strategy to gather and analyze data, providing insights and recommendations for Marks and Spencer and other organizations seeking to improve their employee retention rates.