St Patrick’s Church wished to create additional basement space by excavating below the nave. Archaeology was one of the planning considerations and Pre-Construct Archaeology London were commissioned to undertake an evaluation, and subsequent excavation.

The modern concrete slabs and modern overburden were removed under archaeological supervision using a 3-tonne mechanical excavator. Archaeological recording and hand excavation then took place until a sequence of 17th century dump layers, previously identified during the evaluation were reached. These horizons were removed by machine under archaeological supervision until a solid chalk and mortar surface was revealed. This surface was hand cleaned and recorded before once again being removed by machine. The underlying archaeology was then hand excavated until natural horizons were reached.

The challenges of the job were digging trenches within a working church in the initial period followed by excavation on a large scale within the major refurbishment works, which included removal of large quantities of machine and hand excavated materials.

One significant finding were the remains of a large brick lined cellar of Carlisle House, occupied between 1685 to 1791. The cellar was backfilled in the early 18th century and sealed with a brick floor. To prevent this surface from collapsing into the soft underlying deposits, the floor had been supported by a brick arch bonded directly onto the former eastern cellar wall.

In 1761, a new building, a House of Entertainment, was erected in a garden area for one Theresa Cornelys. This in turn was demolished in 1891. A large foundation wall and several internal walls of this building were archaeologically recorded.

Part of Carlisle House had been converted to accommodate a Roman Catholic chapel and the excavations recorded two brick pier bases and two fragmented mortar floor surfaces associated with this chapel. Following the demolition of Carlisle House, it was replaced with two houses fronting directly onto Soho Square which in turn were replaced by St Patrick’s Church, constructed between 1891 and 1893.

On completion of the excavation the results were documented in an assessment report and later published in The London Archaeologist  Vol. 14, No.9, 2016