All Saints Margaret Street can be found a couple of blocks behind John Lewis's Oxford Street store. It occupies a cramped site, yet the architect William Butterfield was able to make it feel spacious while also fitting in a vicarage and choir school.
Apart from the spire (which led me to discover the church last summer) the exterior is unremarkable without close study, but the interior is spectacular. When you open the door - which is never locked -you are assailed by smoky clouds of incense - intensely holy, but with notes of bacon somewhere underneath.
And then your eyes get used to the subdued light and begin to take in the rich decoration. The church's own website describes it as "a kaleidoscope of coloured tiles, brick, painting and gilding".
All Saints was completed in 1859 and soon became London's unofficial cathedral of High Anglicanism. It is so High that it makes the Pope look like a Strict Baptist.
The choir school lasted until 1968. It was attended by the young Laurence Olivier and William Lloyd Webber (the father of Andrew and Julian) was organist and choir master at All Saints between 1939 and 1948.
If you are still feeling holy, try my posting on Southwell Minster.