The paper presents a 3 degree of freedom UPU mechanism having an excellent practical feasibility. The mathematical model and the design considerations of the 3-UPU mechanism are discussed. A detailed sensitivity analysis is carried out and the results are discussed in a new perspective. A novel design solution for a high precision three axis translation parallel mechanism is presented. We describe and validate the theoretical observations with the prototype model. The capability of the 3-UPU mechanism in performing fine motion manipulation, high precision trajectory following and metrological measurement is demonstrated. The performances of the 3-UPU mechanism concur with the theoretical observations in contrast to what is presented in previous works.