Abstract: An on-demand fluorine cell is described together with the construction of a suitable anode and a means of mounting the anode within the cell. The fluorine cell comprises a cell container having a cathode compartment and an anode compartment, the anode compartment having an anode therein, the cathode compartment and the anode compartment having separation means therebetween so as to separate fluorine gas and hydrogen gas generated during operation of said fluorine cell but said separation means allowing passage of electrolyte between said compartments; said anode extending below a lower end of the separation means and being continuously in contact with the electrolyte, control sensor means in at least one of said compartments to sense the level of electrolyte in said at least one compartment; electric current supply means responsive to signals from said control sensor means so as to either start or stop current supply in accordance with said signals.