By Lucy Kenningham A campaign to save Britain’s ugliest phone booths highlights the subjectivity of beauty, writes Lucy Kenningham Ugliness is subjective. In 1986, the architectural maestros at the Twentieth Century Society slammed the new design of the Great British phone box as “ugly”. Today, the same gang of building nerds is calling for these dirty grey slabs of metal to be bestowed with much-revered listed status, giving them special protection for life. The only thing that has changed since the C20’s campaign to prevent metal phone boxes from being rolled out on the streets of Britain is…