Conversations tail off mid-sentence; students stop to take selfies and parents shield young children’s eyes. The cause of their embarrassment: giant posters of a man wearing nothing but a cowboy hat, a gun holster and a knowing smile. This is John Erik Wagner, and he wants to be Denmark’s next prime minister. It may not be a conventional political billboard but, in this time of frenetic campaigning before the Danish general election this month, every available tree or lamppost is plastered with images of politicians and wannabes, and a relatively unknown candidate needs to work hard to make an impression. For Wagner, a 51-year-old Copenhagener, the way to do that was to bare all.