Where is she now? Barbara Mullen, the misfit model of the 1950s

A streetwise, 'foul-mouthed' New Yorker, Barbara Mullen didn't fit the idea of 1950s glamour, but Lillian Bassman and Richard Avedon still loved to photograph her. John-Michael O'Sullivan tracks down the model who broke the mould - and finds a story of heartbreak and high society