A walk-behind floor treatment machine comprising: a base portion provided with and supported by at least one rotatable work head (27,28) for treating the floor, a handle portion for steering or guiding the machine along a working direction of travel and adapted to be pivotable with respect to the base portion, drive means for rotating the work head with respect to the base portion, floor-engaging wheel means for supporting the handle portion, the wheel means having a substantially transverse axis of rotation with respect to the working direction so as to permit machine travel in the working direction, the wheel means being coupled to the base portion by a linkage which permits vertical travel of the base portion and associated work head or heads (27, 28) with respect to the wheel means, which linkage is attached to the base portion in a configuration which provide transverse constraint to limit or prevent yawing of the base portion with respect to the coupled wheel means, wherein a lower region of the handle portion is pivotably connected (17,19) to the wheel means so that the handle portion may pivot through a vertical arc, and wherein a handle pivot lock mechanism is provided in which the adoption of a predetermined handle portion orientation permits one or more locking feature to act on one or more corresponding constraint feature so as to prevent vertical pivoting movement of the handle portion with respect to the linkage, whereby tilting back of the locked handle portion causes a corresponding rise of the linkage and base portion with work head (27, 28) so as to lift them from the floor, wherein a squeegee suction device is provided for collecting and entraining liquid lifted from a floor surface over which the machine travels, the squeegee suction device being attached to the wheel means via one or more trailing arm which is attached at one end region to the squeegee suction device and at the opposite end region is pivotably attached to the wheel means for pivoting co-axially about the said transverse axis of rotation of the wheel means, the arrangement being such that in use the trailing arm and squeegee suction device may pivot up or down about the transverse axis as they trail behind the treatment machine. a base portion provided with and supported by at least one rotatable work head (27,28) for treating the floor, a handle portion for steering or guiding the machine along a working direction of travel and adapted to be pivotable with respect to the base portion, drive means for rotating the work head with respect to the base portion, floor-engaging wheel means for supporting the handle portion, the wheel means having a substantially transverse axis of rotation with respect to the working direction so as to permit machine travel in the working direction, the wheel means being coupled to the base portion by a linkage which permits vertical travel of the base portion and associated work head or heads (27, 28) with respect to the wheel means, which linkage is attached to the base portion in a configuration which provide transverse constraint to limit or prevent yawing of the base portion with respect to the coupled wheel means, wherein a lower region of the handle portion is pivotably connected (17,19) to the wheel means so that the handle portion may pivot through a vertical arc, and wherein a handle pivot lock mechanism is provided in which the adoption of a predetermined handle portion orientation permits one or more locking feature to act on one or more corresponding constraint feature so as to prevent vertical pivoting movement of the handle portion with respect to the linkage, whereby tilting back of the locked handle portion causes a corresponding rise of the linkage and base portion with work head (27, 28) so as to lift them from the floor, wherein a squeegee suction device is provided for collecting and entraining liquid lifted from a floor surface over which the machine travels, the squeegee suction device being attached to the wheel means via one or more trailing arm which is attached at one end region to the squeegee suction device and at the opposite end region is pivotably attached to the wheel means for pivoting co-axially about the said transverse axis of rotation of the wheel means, the arrangement being such that in use the trailing arm and squeegee suction device may pivot up or down about the transverse axis as they trail behind the treatment machine.