A sliding compound mitre saw comprising: a base assembly (102, 104) connected to a mounting portion; a motor unit pivotally connected to a motor support which is mounted on the mounting portion to allow the motor unit to pivot towards or away from the base assembly (102, 104) to perform chop cuts, wherein the motor support can move relative to the mounting portion to enable the saw to perform sliding cuts, the motor unit having an output drive spindle upon which a circular saw blade can be rigidly mounted to be rotationally driven by the motor unit; characterised in that there is further provided: at least one rearward pivotal guard pivotally mounted on the motor unit which can pivot from a first enclosed position, where it surrounds at least a portion of the lower edge of a saw blade when mounted on the spindle, to a second retracted position where the portion of the lower edge of the saw blade is exposed; and wherein there is further provided a pivotal guard actuating mechanism which moves the at least one rearward pivotal guard from its first enclosed position to its second retracted position when the motor unit is pivoted towards the base assembly (102, 104); wherein the guard actuation mechanism comprises a mechanical linkage having two parts, the first part connected to the rearward pivotal guard, the second part connected to the motor support, one part comprising a cam, the other a cam follower, and being arranged so that, as the motor unit is pivoted towards the base assembly (102, 104), the cam follower rides over the cam to pivot the at least one rearward pivotal guard, wherein there is provided a stop formed next to the cam creating a slot between them in which the cam follower sits when the motor unit is in its upper position, the shape of the slot being such that when the motor unit is in its raised position, the cam follower is prevented from moving and thus locks the rearward pivotal guard in its enclosed position when the motor unit is in its raised position, wherein there is further provided a table mounted on top of the motor unit to enable the saw to act as a table saw. a base assembly (102, 104) connected to a mounting portion; a motor unit pivotally connected to a motor support which is mounted on the mounting portion to allow the motor unit to pivot towards or away from the base assembly (102, 104) to perform chop cuts, wherein the motor support can move relative to the mounting portion to enable the saw to perform sliding cuts, the motor unit having an output drive spindle upon which a circular saw blade can be rigidly mounted to be rotationally driven by the motor unit; characterised in that there is further provided: at least one rearward pivotal guard pivotally mounted on the motor unit which can pivot from a first enclosed position, where it surrounds at least a portion of the lower edge of a saw blade when mounted on the spindle, to a second retracted position where the portion of the lower edge of the saw blade is exposed; and wherein there is further provided a pivotal guard actuating mechanism which moves the at least one rearward pivotal guard from its first enclosed position to its second retracted position when the motor unit is pivoted towards the base assembly (102, 104); wherein the guard actuation mechanism comprises a mechanical linkage having two parts, the first part connected to the rearward pivotal guard, the second part connected to the motor support, one part comprising a cam, the other a cam follower, and being arranged so that, as the motor unit is pivoted towards the base assembly (102, 104), the cam follower rides over the cam to pivot the at least one rearward pivotal guard, wherein there is provided a stop formed next to the cam creating a slot between them in which the cam follower sits when the motor unit is in its upper position, the shape of the slot being such that when the motor unit is in its raised position, the cam follower is prevented from moving and thus locks the rearward pivotal guard in its enclosed position when the motor unit is in its raised position, wherein there is further provided a table mounted on top of the motor unit to enable the saw to act as a table saw.