Brooks' original church plans.
Because of declining congregations, the church was closed and deconsecrated in 1964. The parish at that time was united with St. Leonard's in Shoreditch. Consequently, the St. Michael's building was turned into the home of the London Architectural and Salvage Supply Company Limited in 1976, which occupied most of the space for over thirty years.
In 2007, Westland and Company took over the church to use as showrooms for its architectural garden and decorative antiques business.
A 1908 photo shows what the altar looked like, however, the actual location and current status of the Salviati mosaics in the church that consisted of an "ornamental design" is unknown.
Sources:
Amazon
London Church Buildings
The Independent
Westland and Co.
Church Plans Online
Parliament. House of Commons Papers. Vol. 14, May 4, 1875. 156.
Church Postcard Views
Barr, Sheldon. Venetian Glass Mosaics: 1860-1917. London: Antique Collectors' Club, 2008. 124.