A pumping mechanism comprising: a plurality of peristaltic pumping actuators (44A-44J) configured to sequentially compress adjacent sections of a first portion of an at least partially compressible pumping element having an inlet and an outlet that is downstream of the inlet, the plurality of pumping actuators further configured to reciprocate with a motion comprising a fundamental drive frequency, wherein a last pumping actuator of the plurality of pumping actuators is nearest to the outlet; at least one compensation actuator (45A/45B) arranged to selectively compress a second portion of the at least partially compressible pumping element that is disposed between the first portion and the outlet of the at least partially compressible pumping element, the at least one compensation actuator configured to reciprocate with a motion comprising the fundamental drive frequency at a phase shift relative to the last pumping actuator; a drive shaft configured to rotate with an angular velocity; a plurality of pumping cams (60A-60J) being fixedly coupled to the drive shaft, each one of the plurality of pumping cams configured to cause a respective one of the plurality of pumping actuators (44A-44J) to reciprocate, the plurality of pumping cams comprising a last pumping cam corresponding to the last pumping actuator, each of the plurality of pumping cams comprising a shape comprising a fundamental harmonic frequency and a first amplitude; and at least one compensation cam (64A/64B) configured to cause the respective at least one compensation actuator (45A/45B) to reciprocate, the at least one compensation cam comprising a shape comprising the fundamental harmonic frequency and a second amplitude and a phase shift relative to the last pumping cam, wherein the drive shaft rotates at an angular rate that varies over a 360° rotation, wherein a fundamental drive frequency is determined by the inverse of a time period required for the drive shaft to complete one 360° rotation; and characterised in that the angular rate of the drive shaft that varies comprises one or more integer harmonics of the fundamental drive frequency, the one or more integer harmonics varying from the fundamental drive frequency and being an integer multiple of the fundamental drive frequency. a plurality of peristaltic pumping actuators (44A-44J) configured to sequentially compress adjacent sections of a first portion of an at least partially compressible pumping element having an inlet and an outlet that is downstream of the inlet, the plurality of pumping actuators further configured to reciprocate with a motion comprising a fundamental drive frequency, wherein a last pumping actuator of the plurality of pumping actuators is nearest to the outlet; at least one compensation actuator (45A/45B) arranged to selectively compress a second portion of the at least partially compressible pumping element that is disposed between the first portion and the outlet of the at least partially compressible pumping element, the at least one compensation actuator configured to reciprocate with a motion comprising the fundamental drive frequency at a phase shift relative to the last pumping actuator; a drive shaft configured to rotate with an angular velocity; a plurality of pumping cams (60A-60J) being fixedly coupled to the drive shaft, each one of the plurality of pumping cams configured to cause a respective one of the plurality of pumping actuators (44A-44J) to reciprocate, the plurality of pumping cams comprising a last pumping cam corresponding to the last pumping actuator, each of the plurality of pumping cams comprising a shape comprising a fundamental harmonic frequency and a first amplitude; and at least one compensation cam (64A/64B) configured to cause the respective at least one compensation actuator (45A/45B) to reciprocate, the at least one compensation cam comprising a shape comprising the fundamental harmonic frequency and a second amplitude and a phase shift relative to the last pumping cam, wherein the drive shaft rotates at an angular rate that varies over a 360° rotation, wherein a fundamental drive frequency is determined by the inverse of a time period required for the drive shaft to complete one 360° rotation; and characterised in that the angular rate of the drive shaft that varies comprises one or more integer harmonics of the fundamental drive frequency, the one or more integer harmonics varying from the fundamental drive frequency and being an integer multiple of the fundamental drive frequency.