A cannulation assembly comprising: a housing; a needle selectively extendable from a proximal end of said housing; a tube arranged to pass through the housing and through a bore of said needle such that an insertion end of said tube is arranged to selectively project from an insertion end of said needle; a slide mounted to the needle in sliding engagement with the housing and arranged to move the needle from a retracted position to an insertion position such that the needle projects from said housing; wherein said slide is further arranged to move the needle from the insertion position to a locked position such that the needle is fully retracted.