For 250 years the streets of Spitalfields, next door to the City of London, have provided a haven for a succession of refugee and immigrant communities. Intense overcrowding gave the district a reputation as one of the worst slums in the East End, and its splendid Georgian houses succumbed to decay. The latest wave of incomers are artists, historians, architects -- enthusiasts bent on transforming the derelict houses into highly desirable residences.