A hydraulic system for a working machine of the kind having a chassis 12) and a boom pivotally attached to the chassis, the hydraulic system comprising: a hydraulic fluid reservoir ; a boom actuator configured to move the boom in an ascending direction and a descending direction, the boom actuator having an ascending chamber and a descending chamber ; a first pump ; a first directional control valve comprising a first ascending state configured to direct hydraulic fluid from the first pump to the ascending chamber to move the boom in the ascending direction, a descending state configured to direct hydraulic fluid from the first pump to the descending chamber to move the boom actuator in the descending direction, and a first neutral state where the first pump is isolated from the ascending chamber and the descending chamber; a second pump ; a second directional control valve comprising a second ascending state configured to direct hydraulic fluid from the second pump to the ascending chamber to move the boom actuator in the ascending direction, and a second neutral state where the second pump is isolated from the ascending chamber and the descending chamber; and wherein the second directional control valve further comprises a float state configured to connect one of the ascending and descending chambers to the hydraulic reservoir for permitting the boom to move freely in one of the ascending and descending directions, characterised by : a float valve comprising: a blocked state configured to disconnect the other of the ascending and descending chambers from the hydraulic fluid reservoir; and an open state configured to connect said other of the ascending and descending chambers to the hydraulic fluid reservoir independently of the second directional control valve so that movement of the boom is permitted in the other of the ascending and descending directions. a hydraulic fluid reservoir ; a boom actuator configured to move the boom in an ascending direction and a descending direction, the boom actuator having an ascending chamber and a descending chamber ; a first pump ; a first directional control valve comprising a first ascending state configured to direct hydraulic fluid from the first pump to the ascending chamber to move the boom in the ascending direction, a descending state configured to direct hydraulic fluid from the first pump to the descending chamber to move the boom actuator in the descending direction, and a first neutral state where the first pump is isolated from the ascending chamber and the descending chamber; a second pump ; a second directional control valve comprising a second ascending state configured to direct hydraulic fluid from the second pump to the ascending chamber to move the boom actuator in the ascending direction, and a second neutral state where the second pump is isolated from the ascending chamber and the descending chamber; and wherein the second directional control valve further comprises a float state configured to connect one of the ascending and descending chambers to the hydraulic reservoir for permitting the boom to move freely in one of the ascending and descending directions, characterised by : a float valve comprising: a blocked state configured to disconnect the other of the ascending and descending chambers from the hydraulic fluid reservoir; and an open state configured to connect said other of the ascending and descending chambers to the hydraulic fluid reservoir independently of the second directional control valve so that movement of the boom is permitted in the other of the ascending and descending directions. <EOS>