Abstract: A mobile fuel delivery system and method are described for dispensing fuel in a poorly ventilated area. The system includes a fuel dispensing nozzle for dispensing the fuel; a cargo tank 16 for containing the fuel; a vapour recovery nozzle for recovering vapour from a fuel tank of a vehicle during fuelling; a sealing mechanism for sealingly engaging the fuel tank, a vapour tank 18; a pressure/vacuum release valve 20 connected between tank 16 and tank 18 and which is operable to increase/decrease pressure within tank 16 during dispensing of fuel and recovery of vapour recovered by the vapour recovery nozzle and pumped into the tank 16; and a safety mechanism including a control module 38 and a pressure detector 36 for detecting pressure within the tank 18, the module 38 being operable to stop fuel dispensing when pressure in tank 18 reaches a predetermined pressure.