A tour of the the Eastern (Clifton) side of the Avon Gorge, including caves, forts, tunnels and bunkers.

Led by local artist Heath Bunting.

Heath Bunting (b. 1966) is a Bristol-based artist whose work moved from 1990s net.art into a long physical investigation of hidden ground: caves, tunnels, bunkers, rock shelters and unofficial overnight space. He treats the city’s limestone voids and leftover infrastructure as both research site and living commons.

Between 2003 and 2010 he ran The Tunneling Project and compiled a *Guide to urban underground Bristol*. From 2007 to 2011 he listed *Rock and Breakfast* as informal overnight use of rock shelters. Those mappings still feed the tours he leads on the Clifton side of the gorge. Geology, military leftover, edible plants and a place to spend the night are treated as one continuous practice — a residency walk rather than a heritage trail.

The Avon Gorge is a 2.5 km Carboniferous limestone canyon (SSSI) about 213 m wide and 91 m deep at the suspension bridge. Rare plants, peregrines, jackdaws and horseshoe bats use the cliffs and voids.

Walks start at The Lookout Lectern, opposite No. 2 Sion Hill, Clifton, Bristol BS8 4BA.

Sites visited or discussed

Clifton Rocks Railway. Victorian underground funicular (1893–1934) through a brick-lined tunnel ~450–500 ft long, rising ~200–240 ft at about 1 in 2.2. Water-balance cars; trip about 40 seconds. In WWII the tunnel became an air-raid shelter and housed BBC emergency studios, a relay station, BOAC offices and Civil Defence rooms. Tracks and wartime floors remain.

Hotwells Spring(s). Tepid mineral springs (~24 °C) at the foot of St Vincent’s Rocks, same deep limestone system as Bath, first recorded in 1480. Georgian spa briefly rivalled Bath; first Hotwell House demolished 1822 for Bridge Valley Road; second pump room / Royal Clifton Spa removed 1866–67 when the river was widened. The original spring is lost. Survivals: the 1786 Grade II* Colonnade on Hotwell Road, and a modest remnant of St Vincent’s Spring by the Portway.

Stokeleigh Camp, Clifton Camp and Burgh Walls Camp. Three late Iron Age promontory forts (scheduled monuments, Dobunni territory) within ~800 yards of each other, built to command the Nightingale Valley crossing. Stokeleigh (Leigh Woods, ~7.5 acres, National Trust) is the best preserved, inner bank still rising more than 9 m above the ditch. Burgh Walls, immediately south of the valley, was largely levelled in the 1860s for housing. Clifton Camp sits opposite on Observatory Hill; three ramparts survive despite a later reservoir.

Avon Thrust / historic river crossing (the “Avon Fault ford,” not a “Clifton Submersion Bridge”). Variscan reverse fault: older Clifton Down Limestone thrust ~300 m north over younger Upper Cromhall Sandstone, exposed at Bridge Valley Road / Portway just north of the bridge. Nightingale Valley follows the shattered ground and drops from Leigh Woods to a former low-tide ford. That fault-controlled descent plus the crossing is why the three forts sit where they do. No weir survives at the exact spot.

Giant’s Cave (Ghyston’s / St Vincent’s Cave). Natural chamber in St Vincent’s Rocks, ~250 ft above the river, reached from Clifton Observatory by a 200 ft tunnel and 130 steep steps cut in the 1830s. Tied to the Goram / Ghyston / Avona giant stories. Official entry is via the Observatory; on this walk it is usually discussed from the gorge rather than ticketed from above.

Hotwells railway station. Southern terminus (opened 1865 as Clifton) of the Bristol Port Railway and Pier, almost under the bridge. Closed 1921 for the Portway. Almost nothing remains on the surface. The short tunnel under Bridge Valley Road was a WWII shelter (permit system) and later a gun-club range into the 1990s. The northern BPRP alignment survives as part of the Severn Beach Line.

Clifton Suspension Bridge. Grade I wrought-iron span, 214 m, deck ~75 m above high water. Brunel’s 1831 design, finished 1864 by Hawkshaw and Barlow using Hungerford Bridge chains. Still a working toll bridge; pedestrians and cyclists free. Trust museum on the Leigh Woods side.

School Room Caves (Upper and Lower). Small, little-documented caves on the Clifton cliffs. They appear on Bunting’s walks (and possibly as “Headmaster’s Study” in his underground listing) rather than in standard caving guides. Not show caves; access to Upper cave is unofficial scramble.

“Bristol City Council nuclear bunker.” Not a staffed war room. The council has said it holds no nuclear bunkers. The site usually meant is a ~64–65 m disused Port and Pier Railway tunnel converted c.1940 into a blast-protected records store for deeds and civic papers, in use at least into the 1970s. The longer neighbouring tunnel (~160 m) was a shelter and later a firing range. Now emptied, flooded and sealed. Videos calling it a “control war bunker” are describing this archive.

Jack’s Hole / Gollum’s Cave / J. M. W. Turner’s Cave. Same or adjacent limestone feat

Description supplied by the event organiser.