From chalk mines to nuclear bunkers, hidden churches to battle grounds, Norfolk has a host of forbidden locations where visits are prohibited.

Many are unsafe or downright dangerous while others have been sealed for years. Caution is advised: these sites are closed to the public for very good reason. You have been warned!

The Norfolk chalk mines

From the middle-ages to the beginning of Second World War, Norwich was mined for chalk and flint and today many of the mines, believed to have been dug between the 12th and 18th centuries, still remain underneath the city. No detailed maps of all the mines within the city boundary exist, and therefore a great deal of independent research and exploring has been undertaken in attempt to uncover the exact locations. There are mines and tunnel systems across the city from Earlham Road to Bishopgate, Harford to Thorpe.

There are many risks involved with exploring the mines and a spokesperson from Norwich City Council said: “The majority of chalk mines in Norwich are blocked up and the remainder are inaccessible as they are on private land. Chalk mines are dangerous places because of the risk of collapse should you disturb anything and there can also be a lack of oxygen, so we would strongly advise people against entering them.”

Bawburgh Nuclear Bunker

Deep below the ground just outside Norwich, a six-level-deep bunker was built in the 1950s as a Regional Government Headquarters in the event of a nuclear attack on London. The Eastern Sector Operations Centre had a guardhouse with a rear annex that had a stairwell leading to an access tunnel. Through the tunnel, a three-storey underground operations block with 10-foot thick concrete walls was housed with its own borehole, generators and filtered air. Had London been hit by nuclear bombs and had national government broken down, a network of Regional Seats of Government would have taken over to enforce order, distribute food and co-ordinate the rescue of the sick and injured. It was closed in 1992 and is now privately-owned. There are other bunkers in King’s Lynn, County Hall and RAF Neatishead.

St Mary the Less Church

Hidden in plain sight, this tiny gem is tucked away behind Queen Street – look up when you see the iron gate and you can spot the tower with its bricked-up windows and see a little of the flint-covered porch.

From an unassuming wooden gate on Tombland, you can also see the tower – the gate leads to an alley which leads to the church but which is locked. Once let to the so-called Dutch Strangers, it became a merchants’ hall where Dutch and Walloon cloth was traded and later, in the 1620s, where Worstead cloth makers plied their trade. It later became a French Protestant church, was then owned by protestant cult the Swedenborgians, then the Catholic Apostilic Church, which held services at the church until the 1950s. The building then became a furniture store for Robertson and Coleman until 1985 and is now privately-owned. The last photographs taken of the church show it as essentially a bare shell: Historic England’s website states that Norwich City Council is liaising with the owner regarding repairs.

St Andrew’s Asylum, Thorpe

While the main Norfolk County Asylum has been converted into luxury housing, the annex built to the north in 1876 on the site of a cricket field is now redundant (and much reduced in size). During World War One, the building was used as a War Hospital and in 1920 became the Norfolk Mental Hospital before a final name change to St Andrew’s Hospital in 1923. The Second World War also saw the buildings used as an Emergency Section Hospital for soliders and civilians. Closed in 1998, the site is fenced off and sadly the interior has been vandalised badly.

Sovereign House, Norwich

The former headquarters of the HMSO (Her Majesty’s Stationery Office) between 1968 and 1996, this brutalist office block is part of the Anglia Square shopping centre. Once the workplace of 800 people, it is a glass and concrete building with two spiral staircases and three wings and towers over the St Augustine area of the city. The building is heavily patrolled by security staff and is fenced off: inside there are warnings about unstable rooms and asbestos, along with a roof riddled with yawning cracks in the masonry. Now owned by property developers, the debate over the redevelopment of Anglia Square rumbles on while Sovereign House crumbles on.

Winter Gardens, Great Yarmouth

This once-glittering palace of glass and steel on Great Yarmouth’s Golden Mile is in a sorry state, with broken panes of glass and rusting metal, but a £10 million rescue plan is underway to bring this Victorian old lady back to her former glory. The Grade II-listed landmark is the UK’s last surviving Victorian seaside cast iron and glass winter gardens and was first built in Torquay in 1878. Bought by Great Yarmouth Borough Council it was carefully shipped round the coast by barge and rebuilt on the Golden Mile in 1903. Filled with exotic plants, it gave visitors the chance to enjoy a tropical garden on the east coast of Britain.

It has been a roller skating rink, a venue for concerts, an Austrian-style beer garden with waitresses in Tyrolean costume, an amusement arcade and a concert hall, but today it is vacant, boarded up and waiting for the love it needs to bring it back to life. Work begins next year.

Stanford Battle Area

Close to Thetford, a 30,000-acre expanse of land is where six Norfolk villages once thrived -West Tofts, Sturston, Langford, Stanford, Buckenham Tofts and Tottington. Today, it is a heavily fortified military training ground where visiting is strictly off-limits – Stanta Battle Area is where troops prepare for war. In the mid-1940s, villagers were ordered out of their homes when the army needed a training area as planning began for the invasion of Europe. Families had three weeks from the initial meeting in July 1942 to move out: they would never return. The area became a training ground for soldiers during the run-up to D-Day and since then for those who served in Northern Ireland, the Falklands, the Balkans, Iraq and Afghanistan. In some of the villages, all that remains are humps where the clay lump homes once stood. Elsewhere, pre-war council houses have been shored up and are now used as part of the training operations. The site is vast enough to take a battalion parachute drop from its most frequent customers, the 16th Air Assault Brigade, to host live firing exercises and major mock operations and there is a specially-built fighting village built in the 1960s when the Cold War was at its peak for troop training with the area meant to be like built-up areas on the East German plain. There is frequent live firing on the site.