Snake-like robots have numerous applications in minimally invasive surgery (MIS). One important research topic of snake-like robots is the flexible joint mechanism and its actuation. This paper describes the design and fabrication of a new type of flexible joint mechanism which is enabled by metal powder bed additive manufacturing technique. Kinematics and static models of the flexible joint are presented, which can help in designing and controlling the flexible joint. As a compliant mechanism, the fatigue characteristics of the flexible joint is investigated. Finite Element Analysis (FEA) is also performed aiming for optimising the design process. In the experiment section, model estimation, FEA and experiment validation are conducted for further understanding the characteristics of the flexible joint. An example design that can survive after 100,000 full loading cycles is demonstrated. Finally, different design variations of the proposed method and a multisection flexible endoscope using the proposed design are introduced. The proposed flexible joint has the potential not only in reducing the cost of manufacturing and assembling a snake-like surgical robot, but also benefits for developing of more sophisticated 3D snake robotic structure which has an optimised space for embedded sensing and actuation.