Abstract: A system for delivery of a high viscosity fluid comprises a variable speed pump. A circuit through which the fluid is pumped comprises a loop having a plurality of fluid off-takes from the circuit. A controller controls the operation and speed of the pump, (i) such that the pump pumps the fluid in the circuit in a high pressure mode in which fluid flows from the pump to the fluid off-takes through both ends of the loop. During the high pressure mode, the controller controls the speed of the pump to maintain the pressure of the fluid in the circuit. The controller also controls the operation and speed of the pump, (ii) such that the pump pumps the fluid around the circuit in a low pressure mode during periods when none of the fluid off-takes are being used.