Princess Margaret (Vanessa Kirby) and Group Captain Peter Townsend (Ben Miles) ask the Queen's permission to marry, but Tommy Lascelles (Pip Torrens) and the Queen Mother (Victoria Hamilton) are against it. A newspaper gets wind of the story, and starts publishing articles about the relationship. The Queen originally promises to support Margaret, but on reflection explains that it must wait until Margaret is 25, thanks to the Royal Marriages Act 1772. Elizabeth and Philip take Peter with them on a trip to Northern Ireland to show their support, before he is due to head to Brussels on duty. But the popularity shown to Peter by the press and public causes Tommy Lascelles to recommend that the posting to Brussels happen early, before Margaret returns from a trip to Southern Rhodesia. This affects the Queen's relationship with her sister forever.