Church of St. James the Less, Pimlico

Designed by G.E. Street and built 1858-61, this was the architect's first London church.
 

The design for the mosaic of the "Ascension" on the arch above the chancel was copied from a 25 year old fresco in the church by G.F. Watts, which had deteriorated. The cartoons were taken by a former pupil of Watts, H.L. Moore. The Venice and Murano Glass and Mosaic Company installed the mosaic in 1886.

Sources:
St. James the Less, Vauxhall Bridge Road, London
The Art Journal. Vol. 38. London: 1886. 94.
John Salmon on Wikimedia Commons
NetNicholl's flickr Photostream