This paper describes research work that has been performed at LSBU, using both a laminar burning velocity rig and a small scale cylindrical explosion vessel, to explore the use of very fine water fog, nitrogen dilution and sodium hydroxide additives in the mitigation of hydrogen deflagrations. The results of the work suggest that using a combination of the three measures together produces the optimal mitigation performance and can be extremely effective in: inhibiting the burning velocity, reducing the rate of explosion overpressure rise and narrowing the flammability limits of hydrogen-oxygen-nitrogen mixtures.