The invention provides an apparatus for generating hydrogen including first and second reactant containers linked to a reactor vessel. The reactant containers contain reactants which, when mixed in the reactor vessel, react to form hydrogen gas. Peristaltic pumps pump the reactants from the reactant containers to the reactor vessel. The peristaltic pumps are selected to provide a maximum pumping pressure in the range from 0.1 bar to 10 bar. An electronic control means is programmed to control the flow of reactants to the reactor vessel so as to maintain the pressure of hydrogen gas within the apparatus at a value of no more than 10 Bar.