The incident and Ernie's remarkable resemblance to MacKenzie cause Allied military intelligence leaders Colonel Somerset (Wilfrid Hyde-White) and Colonel Houston (Gregory Walcott) to consider recruiting Ernie (under threat of court-martial) as the General's political decoy, in order to thwart the assassination plot. After Ernie is presented to MacKenzie in person, the General, after some initial reservations, agrees to the plan. MacKenzie's life is at stake because he is the leading strategist in the upcoming invasion of the European mainland; he is set to travel to Invasion Headquarters, adopting Ernie's identity as his disguise and vice versa in order to deceive German High Command. Only Sergeant Twickenham (Terence De Marney), MacKenzie's batman, is made privy to the situation, as he is to help Ernie maintain the deceit. However, the most vital detail – that Ernie will serve as a decoy target for German intelligence – is conveniently withheld from him.