A safety device 20 for shielding a medical needle 25 comprises a needle mount 28 supporting a medical needle and a needle shielding sleeve 34 arranged coaxially with the mount for sliding movement from an initial needle shielding position to a non-shielding position whereat at least the tip of the needle is exposed beyond the sleeve. Either the sleeve 34 or the mount 28 has both an abutment surface 31 and a sliding surface 29. A flexible connection mounts a radially deformable resilient finger 37 on the other of the sleeve and mount so that a first finger part 46 is configured for radial alignment with the abutment surface 31 where the finger blocks movement of the sleeve or for radial alignment with the sliding surface. A control member 40 is slidable coaxially with the sleeve and is co-operable with a second finger part 47 to the other side of said flexible connection. The control member 40 has a set position at which the first finger part is in radial alignment with the sliding surface so allowing movement of the sleeve from its initial shielding position towards its non-shielding position. This causes deformation of the finger which urges the sleeve back to a shielding position. The movement of the sleeve also causes the control member to be displaced from the set position. This movement of the control member 40 drives the second finger part outwardly which urges the first finger part inwardly and so into radial alignment with the abutment surface following the return of the sleeve to a shielding position. Subsequent movement of the sleeve is blocked by the finger engaging the abutment surface.
