With Russia attacking dissidents on our streets and launching a nerve agent attack on an historic city, our thoughts naturally turn to the Cold War of the 50s to 80s. While both sides are investing once more in armaments, we're also facing a new kind of conflict centred round cyberattacks, social media disinformation and manipulation of political and economic processes.

Back in the first Cold War, fears centred round nuclear holocaust. The booklet 'Protect and Survive' was circulated, encouraging the idea that such an event might be survivable. In reality, government planning centred round preserving elements of central and local government, and establishing a network of observer posts which would track and report on radioactive fallout.

The hope was to establish which parts of the country were still capable of sustaining life, and to set up some form of administration (equipped with extreme emergency powers) to mobilise what was left of the population into rebuilding basic services.

The county is full of remnants of these grim times, charted by the website Subterranea Britannica. It lists some forty Royal Observer Corps (ROC) posts, a Regional Government Headquarters, and a number of District and Borough Emergency Centres. Most of these were constructed from 1955 onwards, and demobilised by 1991, when the collapse of the Soviet Bloc removed the threat as it then was.

The ROC shelters were built to a standard design, with a fourteen foot shaft, a store and chemical toilet, and a monitoring room. Various pieces of equipment were installed to measure the power of bomb blasts and the radioactivity generated. Most still remain, though their access hatches are often damaged.

District and Borough Emergency Centres were built to sustain local government, often in the basements of existing buildings. Some remain ready for use on the basis that any major civil emergency might require a designated centre. Castlepoint and Uttlesford both have centres which had usable equipment when visited by members of Subterranea Britannica, although this was some years ago.

These centres have heavy blast-proof doors, decontamination areas, generator rooms, ventilation equipment, toilets, a dormitory and planning rooms set up with communications equipment. Chelmsford on the other hand just had an unprotected basement with an ordinary wooden door.

Of course, the most famous of these relics is the Kelvedon Hatch 'secret bunker', open to the public as a Cold War Museum. Starting life as an RAF control station, this became the Regional Government Headquarters for London.

This goes 125 feet underground, and is entered via an anonymous-looking bungalow which leads to a 100-yard long access tunnel with armoured doors. It could house hundreds of personnel, and still has much of its equipment. The informative displays within give a fascinating insight into just how frightening those days were.