In February 1961, the German Democratic Republic's news agency ADN reported that Kelley had been "harassed", "threatened" and then arrested by police in West Berlin whilst visiting the city in connection with his attendance at a conference for coexistence and disarmament in Warsaw. The West Berlin authorities dismissed the claims, describing the incident as "trivial". In June of that year, Kelley's son Jack, then aged 23, was fined £1 for painting the slogan "ban the bomb" on a bus shelter near Doncaster, but said "it has nothing to do with my father".