An access device and an attachable implement (60; 90) for identifying migration of the access device when the access device extends through the skin of a patient, the access device including an outer surface and an internal lumen and the attachable implement comprising: an attachable implement body comprising cooperating first and second portions (62, 72; 92, 96) and a biasing member; said first portion (62; 92) comprising a coupling surface and a skin contacting surface and said second portion (72; 96) comprising a coupling surface and a skin contacting surface; said first and second portions configurable between a first, open configuration and a second, closed configuration; and said biasing member biasing the first and second portions into the second, closed configuration; said first and second coupling surfaces coupling to the outer surface of the access device and resisting longitudinal movement of the attachable implement along the access device, wherein the first coupling surface and the second coupling surface co-operate to define a recess (79; 98) in the closed configuration, the recess substantially surrounding the perimeter of the access device and substantially matching the shape of the access device; and said first and second skin contacting surfaces being arranged to contact the skin of the patient; wherein in said first, open configuration said attachable implement body is side mountable onto the access device; wherein the recess is defined in a direction that extends away from the skin contacting surfaces of the attachable implement so that when the skin contacting surfaces contact the skin of a patient at the insertion site no portion of the access device is visible between the skin of the patient and the attachable implement; wherein when said attachable implement body is mounted onto the access device the access device extends in a direction transverse to said first and second skin contacting surfaces; wherein when in said second, closed configuration around the access device, said attachable implement body moves with the access device from a first position where the skin contacting surface is adjacent to the patient's skin to a second position where the first and second skin contacting surfaces are remote from the patient's skin, such that an operator may identify that the access device has migrated. an attachable implement body comprising cooperating first and second portions (62, 72; 92, 96) and a biasing member; said first portion (62; 92) comprising a coupling surface and a skin contacting surface and said second portion (72; 96) comprising a coupling surface and a skin contacting surface; said first and second portions configurable between a first, open configuration and a second, closed configuration; and said biasing member biasing the first and second portions into the second, closed configuration; said first and second coupling surfaces coupling to the outer surface of the access device and resisting longitudinal movement of the attachable implement along the access device, wherein the first coupling surface and the second coupling surface co-operate to define a recess (79; 98) in the closed configuration, the recess substantially surrounding the perimeter of the access device and substantially matching the shape of the access device; and said first and second skin contacting surfaces being arranged to contact the skin of the patient; wherein in said first, open configuration said attachable implement body is side mountable onto the access device; wherein the recess is defined in a direction that extends away from the skin contacting surfaces of the attachable implement so that when the skin contacting surfaces contact the skin of a patient at the insertion site no portion of the access device is visible between the skin of the patient and the attachable implement; wherein when said attachable implement body is mounted onto the access device the access device extends in a direction transverse to said first and second skin contacting surfaces; wherein when in said second, closed configuration around the access device, said attachable implement body moves with the access device from a first position where the skin contacting surface is adjacent to the patient's skin to a second position where the first and second skin contacting surfaces are remote from the patient's skin, such that an operator may identify that the access device has migrated.