Improvements in or relating to pressurisation pumps

A pressurisation pump (10) is provided comprising a first plunger (12a,12aF,12b) and a second plunger (12a,12aP,12b), each plunger being reciprocable within a respective plunger bore (26,28) defined by a housing (14), wherein the first and second plungers (12a,12aF,12aP,12b) together with the bores (26,28) define, at least in part, a pumping volume (23). The pump also includes an inlet port (22) and an outlet port (24) associated with the first and second plungers (12a,12aF,12aP,12b). An end of the first plunger (12a,12b,12aF) is arranged to cover the inlet port (22) during a pump delivery stage in which fluid is displaced from the pumping volume, and an end of the second plunger (12a,12b,12aP) is arranged to cover the outlet port (24) during a pump fill stage in which fuel is drawn into the pumping volume.