When war broke out against the United Kingdom in 1800, Staffeldt received command of the brigade that would cover Fredriksvern against an English invasion. But since the war against Britain in the first phase calmed down after the battle of Copenhagen, Staffeldt and his Jäger Corps was transferred back to Kongsvinger, where he for a while became provisional commander on Kongsvinger Fortress. He also received command over Ullensaker light infantry battalion and the southern skier battalion. In 1803 he was promoted to Colonel.