Declassified document reveals role Scarborough's secret GCHQ base played in Cuban missile crisis

The GCHQ base has been operational in the town since World War One, when it observed the movements of the German naval fleet, and moved to its current site beside a caravan park during World War Two, when it originally occupied an underground bunker.

See inside Scarborough's secret GCHQ baseDocuments that have been declassified due to a '50-year rule' which releases them to the general public include intriguing details of the activities of the listening post in 1962, when the world stood on the brink of nuclear war.

During the Cold War, Scarborough's personnel were required to track Soviet naval traffic in the Baltic and merchant shipping in European waters.

Although monitoring the cargo vessels was seen as a relatively mundane task, it suddenly took on high importance when the Cuban missile crisis broke out.

The tension arose when the US were told that the Soviet Union were secretly shipping nuclear missiles to Cuba. There was talk of an American invasion, but instead a blockade on further shipping was enforced. However, there was a fear that some ships en route would attempt to break the sanctions.

The operators in Scarborough's secret bunker reported the positions of these threatening vessels.

The report they sent to the White House, called Soviet Merchant Ship Changes Course, refers to the Kislovodsk, which appeared to have ended its journey and turned back towards the Baltic. Other vessels bound for Cuba returned to port the next day.

Meet the man who operates Yorkshire's most remote railway signal boxThe information received by US intelligence from Scarborough would have reassured them that nuclear war had been averted.

The reports are discussed in a new BBC Radio 4 documentary called The Secret History of GCHQ, which will be broadcast on October 21 at 8pm.

Scarborough's secret spy base

The Yorkshire Post visited GCHQ Scarborough in November 2018, to coincide with the government intelligence organisation's launch of a new work experience scheme to boost awareness of employment opportunities on the base.

The site was built on what was once the town's racecourse - in the 1970s, staff were moved from their wartime bunker to a more modern building above ground level.

You can rent this amazing working lighthouse on the Yorkshire coastMore than 200 people work there, and they aren't allowed to tell those closest to them exactly what they're working on. It also has the capability to function as Britain's main GCHQ base should the primary nerve centre in Cheltenham be destroyed.

Intelligence analysts monitor threats such as cyber security. network defence, human trafficking, child sexual exploitation and drug smuggling.

Twenty years ago, most of the messages they intercepted were in written form, but the sheer volume of digital communications has made their roles significantly more challenging.

Former foghorn station near Whitby for saleThere's also an on-site museum about the history of the facility, which began life as a wireless signal station on the coast, when the telegraph was the main method of communication.