All Saints marked a new stage in the development of the Gothic Revival in English architecture.
The author and columnist Simon Jenkins called All Saints "architecturally England's most celebrated Victorian church", and the architectural historian Simon Thurley listed All Saints among the ten most important buildings in the country.

The design of the church showed Butterfield (in Sir John Betjeman's words) "going on from where the Middle Ages left off" as a neo-Gothic architect.
Previous architecture of the 19th-century Gothic Revival had copied medieval buildings.
But Butterfield departed considerably from medieval Gothic practice, especially by using new materials like brick.
Charles Locke Eastlake, the 19th-century architect and writer, wrote that Butterfield's design was "a bold and magnificent endeavour to shake off the trammels of antiquarian precedent, which had long fettered the progress of the Revival, to create not a new style, but a development of previous styles".
The Victorian critic John Ruskin wrote after seeing All Saints: "Having done this, we may do anything; ... and I believe it to be possible for us, not only to equal, but far to surpass, in some respects, any Gothic yet seen in Northern countries."

Butterfield's use of building materials was innovative.
All Saints is built of brick, in contrast to Gothic Revival churches of the 1840s, typically built of grey Kentish ragstone.
At All Saints, Butterfield felt a mission to "give dignity to brick", and the quality of the brick he chose made it more expensive than stone.
The exterior of All Saints is employs red brick, heavily banded and patterned with black brick, with bands of stone and carved elements in the gate, the church wall and spire.
Decoration is therefore built into the structure, making All Saints the first example of 'structural polychromy' in London.

All Saints is particularly celebrated for its interior decoration.
Every surface is richly patterned or decorated; the floor in diaper patterned tiles, wall surfaces in geometrical patterned brick, tile, and marble, as well as tiles with painted decoration, large friezes executed in painted tiles, a painted ceiling, and painted and gilded timberwork behind the altar.
The architectural historian Nikolaus Pevsner described the interior as "dazzling, though in an eminently High Victorian ostentatiousness or obtrusiveness. ...
No part of the walls is left undecorated.
From everywhere the praise of the Lord is drummed into you."

The rear of the chancel features a series of paintings on gilded boards, within a delicately  carved brightly patterned gothic screen, the work of Ninian Comper and a restoration of earlier work by William Dyce.
The decoration of the Lady Chapel is also by Comper.
The north wall is dominated by a large ceramic tile frieze designed by Butterfield, painted by Alexander Gibbs, and fired by Henry Poole and Sons, installed in 1873.
It depicts a variety of scenes from the Old Testament, a central Nativity scene and depictions of Early Church Fathers, .

The stained glass windows are limited in All Saints due to the density of buildings around the church.
The original windows were designed by Alfred Gérente but his work was not held in high regard and was subsequently replaced.
The large west window, which was originally fitted with glass by Gerente in 1853–58, was replaced in 1877 with a design by Alexander Gibbs based on the Tree of Jesse window in Wells Cathedral.
The glass in the clerestory dates from 1853 and is the work of Michael O'Connor, who also designed the east window of the south chancel aisle which depicts Christ in Majesty with St Edward Martyr and St Augustine.

The baptistery in the south-west corner of the church is noted for its marble tiling which features an image of the Pelican in her Piety in the ceiling tiles, a symbol of the fall and redemption of man.
All Saints marked a new stage in the development of the Gothic Revival in English architecture. The author and columnist Simon Jenkins called All Saints "architecturally England's most celebrated Victorian church", and the architectural historian Simon Thurley listed All Saints among the ten most important buildings in the country.
The design of the church showed Butterfield (in Sir John Betjeman's words) "going on from where the Middle Ages left off" as a neo-Gothic architect. Previous architecture of the 19th-century Gothic Revival had copied medieval buildings. But Butterfield departed considerably from medieval Gothic practice, especially by using new materials like brick. Charles Locke Eastlake, the 19th-century architect and writer, wrote that Butterfield's design was "a bold and magnificent endeavour to shake off the trammels of antiquarian precedent, which had long fettered the progress of the Revival, to create not a new style, but a development of previous styles". The Victorian critic John Ruskin wrote after seeing All Saints: "Having done this, we may do anything; ... and I believe it to be possible for us, not only to equal, but far to surpass, in some respects, any Gothic yet seen in Northern countries."
Butterfield's use of building materials was innovative. All Saints is built of brick, in contrast to Gothic Revival churches of the 1840s, typically built of grey Kentish ragstone. At All Saints, Butterfield felt a mission to "give dignity to brick", and the quality of the brick he chose made it more expensive than stone. The exterior of All Saints is employs red brick, heavily banded and patterned with black brick, with bands of stone and carved elements in the gate, the church wall and spire. Decoration is therefore built into the structure, making All Saints the first example of 'structural polychromy' in London.
All Saints is particularly celebrated for its interior decoration. Every surface is richly patterned or decorated; the floor in diaper patterned tiles, wall surfaces in geometrical patterned brick, tile, and marble, as well as tiles with painted decoration, large friezes executed in painted tiles, a painted ceiling, and painted and gilded timberwork behind the altar. The architectural historian Nikolaus Pevsner described the interior as "dazzling, though in an eminently High Victorian ostentatiousness or obtrusiveness. ... No part of the walls is left undecorated. From everywhere the praise of the Lord is drummed into you."
The rear of the chancel features a series of paintings on gilded boards, within a delicately  carved brightly patterned gothic screen, the work of Ninian Comper and a restoration of earlier work by William Dyce. The decoration of the Lady Chapel is also by Comper. The north wall is dominated by a large ceramic tile frieze designed by Butterfield, painted by Alexander Gibbs, and fired by Henry Poole and Sons, installed in 1873. It depicts a variety of scenes from the Old Testament, a central Nativity scene and depictions of Early Church Fathers, .
The stained glass windows are limited in All Saints due to the density of buildings around the church. The original windows were designed by Alfred Gérente but his work was not held in high regard and was subsequently replaced. The large west window, which was originally fitted with glass by Gerente in 1853–58, was replaced in 1877 with a design by Alexander Gibbs based on the Tree of Jesse window in Wells Cathedral. The glass in the clerestory dates from 1853 and is the work of Michael O'Connor, who also designed the east window of the south chancel aisle which depicts Christ in Majesty with St Edward Martyr and St Augustine.
The baptistery in the south-west corner of the church is noted for its marble tiling which features an image of the Pelican in her Piety in the ceiling tiles, a symbol of the fall and redemption of man.
All Saints, Margaret Street