Like most City churches, St. Magnus the Martyr lost much ancient glass to the hazards of fire and war, but the extreme north-west window bears armorial glass of 1671 from the former Plumbers' Hall, alongside other livery companies' arms by A.L. Wilkinson (1953-60). On the south aisle, four windows by Lawrence Lee (1949-53) portray St. Magnus and his ancient church at Egilsay, St. Margaret with her lost church in New Fish Street, St. Thomas with his erstwhile chapel on old London Bridge, and St. Michael with his lost church in Crooked Lane.