When the Seven Years' War broke out Spörcken was part of the Army of Observation established to defend Hanover and its neighbours from the French. Following the Battle of Hastenbeck the Army retreated and was eventually forced to conclude the Convention of Klosterzeven taking Hanover out of the war. This soon came under fierce attack in Britain and Prussia, with Frederick II of Prussia suggesting that the army should be reformed under the control of Spörcken.