Like the neighbouring Bellingham Estate, Downham was one
of the cottage estates developed by the London County Council in the inter-war years. Built between 1924 and 1930 to plans by the LCC architect George Topham Forrest, it provided 7,000 new homes. The site for the Catholic church and school was acquired for
£1450 at the heart of the estate, adjoining the large park called Downham Fields.
Mass was said from April 1927 at the Studio Club, by Canon William H. Monk, then financial secretary and resident at the Convent, Belmont Hill, Lewisham. The first
resident priest was Fr Joseph Simmons (from December 1928). As at Bellingham, initial efforts were directed towards the building of a primary school, while a temporary church was erected. The first church on the site was a hall, erected at a cost of £1800
and used for the first time on 20 October 1929. The primary school opened on 26 August 1930, and the presbytery was in use by about 1932. Two extra chapels were added to the church in 1934 and 1935.
Building work for the present church started in February
1961 and the foundation stone was laid on 16 September 1961 by Bishop (later Archbishop) Cowderoy. It was largely complete by 1962 and was opened on 27 October 1963. The architect was Donald Plaskett Marshall & Partners and the builder was T. J. Nally
of Connaught Construction Ltd. The cost was £40,000. Photos of a model of the church in 1961 show a 90ft-high tower beside the west front; the current brick stump at the southwest
corner might be the remnant of the tower.
The sanctuary was reordered in the 1970s when the original altar was moved further west and a stained glass window was installed at the east end. The window had been brought to Downham from the Convent of St
Philomena at St Mary Cray, Kent. The church was dedicated on 25 November 1984 by Archbishop Bowen.
The church is facing south; however, this description will follow the conventional liturgical orientation.
The church is a modern and functional
building, built with a reinforced concrete portal frame. In plan, it consists of a single volume nave and sanctuary, with a sacristy extension to the southeast. Originally, it appears
to have had a tower to the south of the west front, which was either not fully built or radically shortened. The pitched roof has a short pinnacle above the sanctuary area.
Internally, there is a narrow one-bay lobby and a nave of six bays, followed
by a sanctuary of two bays. Every second bay there is a gabled clerestorey window. There is an organ loft at the west end. Furnishings include the black marble sanctuary furniture of altar, tabernacle stand, lectern and font, as well as the east window. Originally,
the east wall was part glazed, part panelled in wood until the current window was installed in the 1970s. The window was designed and constructed by Hugh Powell in 1965 for the Convent of St Philomena at St Mary Cray, from where it was moved to Downham. It
is made from hand-made antique glass and epoxy resin with slate powder in a technique called ‘Resglaze’, invented by Powell.