While I love the stone that has been used to build London, from the Cornish granite to the Collyweston slate, really it is brick that built London. The vast majority of houses built in the 17th to 19thC in London were built from the brickearth and the clay that lies at or near the surface of London. Most people know about clay and how it is made into bricks, pottery and tiles but in London brickearth too was of great importance. Brickearth is a windblown loess, loess being an “aeolian (windborne) sediment being an accumulation of 20% or less clay and the balance of mainly equal parts sand and silt”,  that accumulated at the end of the last Ice Ages between 10 and 20, 000 years ago, so geologically very very recent.  The British Geological Survey describe brickearth as “Varies from silt to clay, commonly yellow-brown and massively bedded.”  Tbh ‘brickearth’ is a somewhat vague term due to this and so is technically called Langley Silt Complex.  but it was perfect for making bricks and was common across London.
And so brickfields and brick kilns popped up wherever new houses were to be built. Look at any 19thC map of London and you’ll see them. In their dozens. But there’s very little evidence of any of this vast industry today. The bricks are there to see in their billions across London, but apart from a few street names, Brick Lane most obviously, the brickfields and kilns have almost entirely disappeared. This is understandable. The brickfields were filled in, with London’s waste, then mainly ashes and street sweepings, and then houses built on them. And the kilns were never more than temporary structures unlike the massive kilns later built by London Brick Company in Bedford and Peterborough or Smeeds in Murston. [ posts to follow! ]
But one kiln survives in London ! It’s in Notting Dale, on Walmer Road and is a bottle or beehive kiln. It’s though unclear though if it was a brick kiln or a pottery kiln as Historic England state “The monument includes a part-restored 19th century updraught kiln, a type often referred to as a ‘bottle kiln’ for the shape of its roof, which was used in the production of pottery. It is situated on Walmer Road, east of Avondale Park and just north of the street known as ‘Pottery Lane’.”  The area was called The Potteries and the Piggeries 
Atlas Obscura says the kiln was built in 1824 and that “One kiln belonging to the original resident brick makers survived and has been extended and turned into a house.” which sounds great but I don’t think is entirely true looking it closely! Historic England do note it has been converted though for domestic use.
The LCC Survey of London states that close to where the kiln is, “some sixteen acres of adjoining land to the west were being dug for brick earth by Stephen Bird, one of the principal brickmakers in London and also a builder active in Kensington;” It continues “The manufacture of pottery appears to have been established here before 1827 by Ralph Adams of Gray’s Inn Road, brick- and tilemaker, who between 1826 and 1831 was the building lessee for most of the houses in Holland Park Avenue between Ladbroke Grove and Portland Road, the earth for the bricks having been no doubt dug from the Potteries area. The ratebooks first refer to this locality as ‘the Potteries’ in 1833. The tithe map of 1844 shows what appears to be a kiln on the east side of Pottery Lane near the present No. 34. The only kiln shown on the Ordnance Survey map surveyed in 1863 is that which still stands on the east side of Walmer Road opposite to Avondale Park.”
They note that the land “The Adams family’s business was chiefly concerned with the production of drain-pipes, tiles and flower-pots” but also refer to the “four and a half acres of derelict ground known as Adams’ Brickfield” which was directly opposite to where the kiln stands. And they note “The kiln was rebuilt by Charles Adams in 1879.” So I wonder whether it was originally a brick kiln that was repurposed at this date for pottery? 
Just to confuse things further, Wikipedia says that “According to the Victorian author and philanthropist Mary Bayly, the local soil was not brickearth but “almost entirely composed of stiff clay, peculiarly adapted for that purpose [brick making]”. from Bayly, Mary, Ragged homes, And How To Mend Them, London (1859) 
And something about the area. I thought this area was/in Notting Hill. But I think Notting Hill doesn’t go much west of Clarendon Road. And I’ve seen it called North Kensington but I think that is now more correctly north of The Westway. So I’ve I think the kiln is actually in Notting Dale which I had never heard of.  My excuse is I’ve been in east London most of my life! 😀
According to Atlas Obscura the area known as the Potteries and Piggeries ” … started with the pig keepers who had recently been forced out of Tottenham Court Road, [and] the community expanded with the arrival of the infamously rowdy brick makers. They built large kilns to fire up their tiles and bricks, and supplied these to line London’s houses. “
The area had some of the worst housing in London “…so bad that in 1850, Charles Dickens called the area, “a plague spot scarcely equalled for its insalubrity by any other in London. … The clay holes caused the area to become rife with stagnant pools filled with water, sewage, and pig slurry. One hole was so large and foul it was dubbed “the ocean.” [ This was in what became Avondale Park. ]  See map of 1848 here with The Ocean shown. 
And disgracefully this area has stayed poor and very much poorer than it’s mega-wealthy neighbours of Notting Hill and Holland Park to this very day, blighted until the late 20thC by slum housing, even with large scale social housing projects from the late 19thC onwards, and infamous both for the slum landlord Peter Rachman  and the racist Teddy Boy riots of the 1950s.  And while housing has improved, the blind indifference to the poor people of this area by the Tory Royal Borough of Kensington and Chelsea culminated in the horrific mass manslaughter of the Grenfell Tower fire in 2018. 
See this article on “The Rift Between Notting Hill and Notting Dale” here.  And bringing it all back around a photograph of #Justice4Grenfell on the kiln.
The area has been massively re-developed since the 19thC and few streets from then remain for which the bricks made here would have been used. St Anne’s & Avondale Primary School maybe? And the streets north of Stoneleigh Place like Ashleigh Rd and Stoneleigh Rd, with it’s decorative tiles, may well have been fired in this kiln. And most likely the many still standing streets in North Kensington.
The kiln is on Walmer Rd in Notting Dale, 10 mins walk south from Latimer Rd Tube Station on the Circle and Hammersmith and City lines, 10 minutes north of Holland Park Tube on the Central Line and 15 minutes west from Notting Hill Gate on the Circle and District Lines.
 Survey of London: Volume 37, Northern Kensington. Originally published by London County Council, London, 1973. british-history.ac.uk/survey-london/vol37/pp340-355