The current paper aims to fill this gap through case-based research, understanding from empirical data the application of Lean 4.0 in four UK companies. The findings showed that Lean 4.0 represents an excellent strategy to improve the manufacturing systems’ performance, mainly productivity, flexibility, real-time data accessibility, and quality control. Also, it was possible to confirm that financial resources, adversity to change, and process complexity are the main barriers to Lean 4.0.