An apparatus 100 for use with a syringe for providing a safety syringe, the syringe having a plunger 110 configured during an inward stroke to expel a substance from a hypodermic needle 102 attached at an open end of a barrel 104 of the syringe, comprises a biasing member 125a, 125 which biases a sheath 106 towards a closed position at least partially covering the hypodermic needle. The biasing member is configured to be released at a point on the inward stroke of the plunger (for example as a result of a force applied by a user on the plunger) to urge the sheath towards the closed position. The plunger and sheath may be coupled together and decouple in order to release the biasing member, and the sheath may be locked in the closed position. A kit of parts comprising the sheath and biasing member is also anticipated.
