A gear pump (1) for use with a hand-operated tool (200) having a rotatable shaft (201), said gear pump (1) comprising: a housing (5) having a chamber (6), an inlet (65) for fluid into the chamber (6) and an outlet (66) for fluid from the chamber (6); and a gear assembly (2) comprising at least one gear (21) mounted for rotation within the chamber (6) between the inlet (65) and outlet (66), and a drive shaft (24, 25) extending from the gear (21) and externally of the chamber (6), wherein a tool-engaging end (25) of the drive shaft (24, 25) is engageable with the rotatable shaft (201) of the hand tool (200) such that rotation of the drive shaft (24, 25) by the hand tool (200) causes fluid to move between said inlet (65) and outlet (66).