A harness for use with breathing apparatus, comprising: a back plate; two support straps, each of which extends between an upper part of the back plate and a lower part of the back plate, the two support straps being disposed on opposite sides of a central axis of the back plate; and a tension equalising mechanism connected to the support straps and being arranged such that, when tension is applied to a first strap of the support straps, it acts to transfer the tension to the other, second strap, thereby increasing the tension in the second strap, characterised in that the tension equalising mechanism includes first and second tension accommodating means which are disposed on opposite sides of the central axis of the back plate and are connected by a connecting element, wherein, when tension is applied to the first support strap, the first tension accommodating means acts to increase an effective length of the first support strap and to reduce the tension in the strap, and the tension is transferred via the connecting element to the second tension accommodating means, which acts to reduce an effective length of the second support strap and to increase the tension in the second support strap; wherein the first and second tension accommodating means are axially and rotatably mounted to the back plate about first and second rotational axes, respectively, and act to reduce or increase the tension in the first or second support straps by rotation about the first and second rotational axes, respectively; the harness further comprising first biasing means for urging the first tension accommodating means to a central return position and/or second biasing means for urging the second tension accommodating means to a central return position, so as to resiliently bias the tension equalising mechanism towards a neutral configuration. a back plate; two support straps, each of which extends between an upper part of the back plate and a lower part of the back plate, the two support straps being disposed on opposite sides of a central axis of the back plate; and a tension equalising mechanism connected to the support straps and being arranged such that, when tension is applied to a first strap of the support straps, it acts to transfer the tension to the other, second strap, thereby increasing the tension in the second strap, characterised in that the tension equalising mechanism includes first and second tension accommodating means which are disposed on opposite sides of the central axis of the back plate and are connected by a connecting element, wherein, when tension is applied to the first support strap, the first tension accommodating means acts to increase an effective length of the first support strap and to reduce the tension in the strap, and the tension is transferred via the connecting element to the second tension accommodating means, which acts to reduce an effective length of the second support strap and to increase the tension in the second support strap; wherein the first and second tension accommodating means are axially and rotatably mounted to the back plate about first and second rotational axes, respectively, and act to reduce or increase the tension in the first or second support straps by rotation about the first and second rotational axes, respectively; the harness further comprising first biasing means for urging the first tension accommodating means to a central return position and/or second biasing means for urging the second tension accommodating means to a central return position, so as to resiliently bias the tension equalising mechanism towards a neutral configuration.