The interior space of St Mary-at-Hill is roughly square in plan, and of a similar size to All Saints'. To the west is the tower, again flanked by a north and south narthex. Wren spanned the square space by a barrel vault in a Greek-cross plan, with a dome at the centre, supported on four columns. If Henry Bell drew his inspiration from any one of Wren's churches, this would be the one. The barrel-vaulting though in All Saints' is much flatter than in St Mary-at-Hill, which has semi-circular vaulting. The dome in All Saints' is more hemi-spherical, and the columns at St Mary-at-Hill are Corinthian with fluting. The Mayoral Seat dominates the pews on the south side, and in the north aisle there is a Consistory Court. Icons of Saint Peter and Saint Katharine are situated at the east end before the steps in to the Quire, and these were painted for the church in 2001 to reflect the parish boundaries, which include the site of St Katharine's Church (demolished) and St Peter's Church.