Updated 3 October 2026

The secret underground city at Corsham tells an extraordinary chapter of British history: former Bath stone workings adapted for wartime industry and, later, a government headquarters intended for use in a nuclear crisis.

From Bath stone to wartime use

The underground quarries grew alongside the demand for building stone and the arrival of the Great Western Railway. In the years before the Second World War, parts of the workings were converted into ammunition-storage facilities. Wartime activity also included an underground aircraft factory.

The Ministry of Defence’s illustrated history explains how these different uses developed. It is important to distinguish the wider quarry network from the later government bunker, rather than treating every underground chamber as one installation.

A secret underground city for Cold War government

In the 1950s, work created a potential relocation site for central government. Known as the Central Government War Headquarters and by codenames including Burlington, it was designed to support government operations below ground.

Historic England’s records describe accommodation for the Prime Minister, operations rooms, a telephone exchange and a radio studio. These practical spaces make the story especially striking: an emergency headquarters needed places to work, communicate and live, not simply shelter.

Messages below ground

Communication was central to the plan. Alongside telephone facilities and a radio studio, a Lamson pneumatic-tube system carried messages through the complex. These surviving elements are recorded separately in the National Heritage List for England.

Explore the history through official sources

The site was declassified in 2004. Declassification does not establish public visitor access, so this article makes no promise of entry or tours. Use the official records and illustrated booklet to discover the story.

• Ministry of Defence: Corsham Tunnels — A Brief History (PDF)
• Prime Minister’s rooms and operations rooms
• GPO telephone exchange
• Radio studio
• Lamson terminus and fan room

Discover Box above ground

Lorne House is a base for exploring the village and the surrounding area. Our Box walks guide points to public routes, while Hidden Box introduces more of the locality’s history.

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Updated 3 October 2026

Box walks bring together valley views, old mills, stone-quarrying history and Brunel’s railway. A useful starting point is the Box Heritage Trail, with a published route and map from the Cotswolds National Landscape.

Box walks: start with the Heritage Trail

The official guide describes a 4.5-mile circular route through the By Brook valley. It includes steep sections and is graded for walkers with moderate fitness. Use the current guide to judge the route against your own abilities, the weather and the time available.

View the official route and download the map

The route links the village’s mills, quarrying landscape and railway heritage. It also passes Lorne House, whose Awdry connection gives this local walk an extra layer of interest.

Box Tunnel and the railway

Box Tunnel is one of the village’s defining landmarks. The heritage trail includes a viewing point for its western portal and explains the surrounding railway features. Follow the published route and public paths; railway land and the tunnel itself are not places to explore on foot.

The same railway landscape helped inspire the young Wilbert Awdry. Read the story of Lorne House and Thomas the Tank Engine before setting out.

Quarry woods, views and a pub stop

The official trail crosses Box Hill Common and passes through Quarry Woods, with an optional extension towards Hazelbury Manor. Stay on public paths: references to old workings are historical context, not an invitation to enter quarry shafts or mine passages.

The route also passes the Quarryman’s Arms. For food stops, opening and booking information, see our Food & Drink guide and check directly with the venue.

A shorter village outing

If the full trail is more than you want, start with Box Parish Council’s visitor information and our Box guide. Our Hidden Box article gives some background to the village’s buildings and stories.

Real World Studios is a working recording facility rather than a public touring attraction. Enjoy the village from public routes and respect private property.

Little Solsbury Hill

For another walking option near Bath, the Cotswolds National Landscape publishes a Little Solsbury Hill circular walk. Check its current route details and suitability separately; it is a different outing from the Box Heritage Trail.

Plan your stay for Box walks

Check the latest route information before leaving, allow for hills and road crossings, and choose footwear for the conditions. For more days out to combine with your walk, explore Things to Do.

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