There is stained glass by the Chance Brothers and the Bromsgrove Guild and an organ by George Pike.
Construction commenced in 1727 and was completed in 1736. In a simple crucifix form, the outside is of red brick, dressed with stone. Surprisingly, there are no foundations as we would recognise them today. When built, there was no tower, no side porches, no vestry, a flat face and everything was simple and symmetrically balanced, including the balustrade on the front and side of the building.
This simple elegance continued inside the building. The entrance at first was at the back of the building, not through the existing porches, but through the doors which today lead into the church itself. There was no stained glass so light would have flooded in from the large clear windows, some of which still retain their original Georgian glass behind the Bromsgrove Guild inserts. Looking down the church, towards the altar, you see Tuscan columns on high pedestals. The columns are made from wood and traditionally believed to have been turned from trees growing on the site and subsequently plastered.
Built directly on the soil, without any real foundations, the ground was covered with white stone and pews floored with wood. It is not known who the architect was however the design has similarities with those by James Gibbs. The Holy Ghost plaque in the ceiling of St Thomas’ closely resembles that at St Peter’s on Vere Street, London and we know that Gibbs designed St Peter’s.
The tower was completed in 1759. In 1809, the barrel organ was replaced by a ‘finger’ organ in the West gallery, costing £420. It was manually blown with a case made of Spanish mahogany. The organ can now be seen behind the choir stalls, where it was moved in 1890. The builder was George Pike England, In 1826 the first stained glass window was installed. The 'Incredulity of St Thomas' was made by the Chance Brothers of Smethwick who also glazed Crystal Palace and the Houses of Parliament.
The crowning glory of the New Chapel was the arched barrel ceiling. It is this unique feature, more than any other, that gives St Thomas’s its Grade I listed status.