
The street in which it stands runs along the south side of the line of the City's Roman and mediaeval wall. A stretch of the wall can be seen in the churchyard, west of the church, and the north vestry is semicircular because it sits upon the base of a bastion of the City's wall. All Hallows' has an austere exterior. Its brick-built south elevation has just three large semicircular lunettes high up in the wall. The stone-faced west tower stands forward of the nave and is unremarkable except for its pedimented Tuscan doorway and domed cupola. The cross and ball were added by Sir Arthur Blomfield in 1898 on the model of St Paul's Cathedral for Samuel John Stone, Rector.
Fluted Ionic columns articulate this light Classical interior by George Dance the younger. The coffered apse houses a painting of Ananias restoring St Paul's sight.
The interior is a surprise after the plain exterior. It is aisleless and is structurally undivided. Thin, fluted Ionic columns stand against the side walls and mark out three principal bays. There is a light frieze that runs round the church, but no cornice. The columns appear at first glance to support arcades, because the arches of the lunettes and their indentations into the barrel-vault seem to rest on them. The vault has shallow coffering. The chancel is marked out by a low wooden screen of 1962, which can be raised if required. The pulpit stands against the north wall and can be entered only from the vestry. It is a three-decker that has lost its lowest deck. The pews have been removed, but choir-stalls remain. The west gallery, which rests on Tuscan columns, houses the organ.