Ironside began on 23 May 1944 with the aim of having the threat established by 29 May and continued until 28 June (22 days after the Normandy landings). It was implemented via double agents, in Britain and the United States, under the control of the Twenty Committee. The operation did not receive any resources from the Allied navies or airforce, so the deception had no physical element. This meant that Ironside had none of the traditional accompaniments to an invasion, including reconnaissance flights, bombardment, and naval operations. As a result, the Twenty Committee was cautious about using important agents to pass over the deception.