Preparing for Nuclear War 1961-1991

English Heritage

York Cold War Bunker

York Cold War Bunker
The Group Headquarters of Royal Observer Corps (ROC) Branch 20 was built in 1961. Its function was to identify and record nuclear explosions, plot their location and power and measure ensuing radiation levels. 

The mass concrete structure is part-sunk into the ground within a housing estate on the outskirts of York.

The Headquarters was designed to act as a nerve centre in the event of an attack.

60 volunteers from the ROC were to man it at times of crisis, along with a team of scientific advisers from the UK Home Office.

The building was closed in 1991 but retained many of its interior fixtures and fittings. After a period of extensive conservation, the site was opened for public tours in 2006.

How ROC Volunteers Plotted Nuclear Threat
In this imagined scenario, we track the procedure that would have been followed in the event of a nuclear attack. 

'TOCSIN!' A nuclear bomb has been detonated over the docks at Hull. In the surrounding area, tiny concrete bunkers relay its information to the Headquarters in York.

Across Britain, a network of tiny three-man monitoring posts were equipped to measure the orientation and altitude of a nuclear explosion, its power and the resultant radiation levels.

As each bomb detonated, this core information was to be communicated to Post Display Plotters in the Group Headquarters. Each new bomb would be announced to colleagues in the operations room with the codeword ‘TOCSIN’.

The record of a city’s decimation is written on a small paper docket and passed from hand to hand to be triangulated.

Eight plotters would have recorded information from the monitoring posts, writing the details on small paper dockets.

Standing behind them, a ‘runner’ would have been ready to take the docket and walk the few steps to the triangulation table.

Using a protractor and rule, the grid reference of the bomb is calculated.

As reports of explosions came in from outlying posts, ROC officers were to triangulate this data to pinpoint the exact location of the detonations.

Each outlying monitoring post would have had a corresponding socket on the triangulation map. A protractor was slotted into the socket and used to mark a bomb’s bearing.

The bomb’s vital statistics are recorded for posterity on the Nuclear Burst tote. As further bombs fall, a new line is entered on the ledger.

The nuclear burst tote, a large wall chart where numbers would be entered, was carry a record of all bombs reported in the Yorkshire area. It would have recorded grid references, altitude, power and time of detonation.

The bomb is transcribed again, this time to a bomb slat which is slotted into a tall frame so that all in the control room could see.

Bomb details were to be recorded using chinagraph pencils on wooden slats with wipe clean acrylic covers. As each bomb was notified, a new slat was raised up to be visible to everyone in the operations room. Up to 20 bombs could be listed at any one time.

As supervisors and officers take in the news, the bomb’s data is again rewritten – this time typed into a computer terminal. As ‘enter’ is pressed, news of the bomb travels across the country. Its existence has been announced to the world.

Bomb data was to be typed into this terminal on the operations room balcony. From here, the information would have been communicated to ROC sector control, and then on to military and civilian administrators.

A minute later, the presence of the bomb is relayed back into the headquarters through the communications hub. It is official. The bomb exists.

Status reports from across Britain would have been processed in the communications hub. A teleprinter would be patched into PTR B –DSP A in order to churn out bomb bursts, first fallouts and post status reports from adjacent ROC groups.

An operator would then pass this information to officers using the main display screens.

Here, the bomb is again plotted. Over the next few weeks a plume of radiation will be traced, giving some warning to those who live in its path.

The officer at Display ‘A’ was to mark the bomb’s location on the map – green for ground burst, orange for air.

Writing back to front so that the text could be read from the other side of the display, the bomb would have been designated a number and time.

That process happens over the coming weeks, but for now…


Credits: Story

Kevin Booth, Rose Arkle

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