Only two bomber groups remained under Sperrle's command at the end of 1941 for direct attack on Britain. The anti-shipping mine-laying force around Britain did not receive the support it required through the war, and the German effort remained half-hearted. Sperrle protested to the OKL, OKW and Göring upon the dissipation of mine-laying operations through 1941 and 1942. Greim's air corps was designated as leader of the effort in an effort to revitalise the campaign, but due to the demands of the Eastern Front, Greim departed in December 1941.