Great Britain 1987 31p Europa, British Architects error, SG1357aGreat Britain 1987 31p Europa "Stuttgart Staatsgalerie" British Architects, SG1357a A superb unmounted mint, with full original gum, example of the rare partially perforated error, presented as a bottom left hand corner marginal cylinder block of sixteen. This remarkable piece contains: One completely imperforate horizontal pair (lower left), Seven partially perforated stamps, and Seven normally perforated stamps. A visually striking and significant