1. Many of London’s ancient lost rivers still through the city. This is the river Tyburn, which runs from Hampstead through Regent’s Park and into the Thames.
Many rivers were built over as London grew, and some, like the Tyburn, were converted into sewers in the 19th century by Sir Joseph Bazalgette.
2. This junction of two sewers near Stockwell tube station shows how beautiful much of the sewer network is.
3. This is an overflow sewer flowing into the Fleet sewer at Farringdon Street.
4. The sewer network is full of striking junctions like this.
This is the Clapham Storm Relief sewer.
5. This is where a sewer was dropped to a lower level during the building of the Metropolitan tube line, north of Hyde Park.
The photographer says it’s rare to see a ramp like this and handrails to guide people down.
7. Meanwhile, the gargantuan Crossrail project has put a vast new layer of tunnels through London’s underbelly.
The tunnels will link national rail services with the London Underground and provide a quicker way to travel from east to west across the city.
8. The photographers behind the Subterranean London book accessed this National Grid excavation, part of the Crossrail network, by climbing down 12 storeys.
9. The Crossrail tunnels – seen here underneath Whitechapel station, 32 metres below street level – are vast and were built with a 150-metre-long boring machine.
The completed Crossrail network will include 19 miles of tunnels.
10. The machine that made the tunnels weighs 1,000 tonnes and its cutting tool is seven metres across.
11. But perhaps the most remarkable part of London’s hidden underground is its disused railway networks and stations.
This is part of a 6.5-mile-long railway owned by Royal Mail that was once used to ferry post across the capital, but is now disused.
The network was built in 1927 and stretches from Paddington to Whitechapel. Both the line and its stations are remarkably well preserved.
12. Aldwych tube station shut in 1994. It was originally known as Strand and was used as an air-raid shelter during the Second World War.
13. There are occasional tours, and it’s sometimes used for filming.
14. A train is stationed by one of the platforms for filming purposes, but the rest of Aldwych station has fallen into disrepair.
16. There are still instructions up for people using it as an air-raid shelter.
19. Brompton Road station was once on the Piccadilly line, but was closed and later used as a military office. This map, which dates from the Second World War, shows gun placements across London.
According to Londonist, which gained access to the station in 2011, the station was closed in 1934, and much of the structure was sold to the Ministry of Defence.
The site was bought in 2013 for £50 million to be turned into flats.
Subterranean London, compiled by Bradley L. Garrett with a foreword by Will Self, is published by Prestel.