Illuminated signs on the M5 motorway warn of delays at Junction 11 from tomorrow, 29th September until the end of March. The junction is to be upgraded. Not before time, the huge volume of traffic bound for GCHQ causes tailbacks from the roundabout onto the southbound carriageway of the motorway.

The traffic conditions are very different from those at the other GCHQ.

If you drive the road from North Cornwall toward North Devon, an intriguing sight appears to the  left-hand side. Set back a couple of miles from the road, there is a cluster of large white satellite dishes. What possible purpose could there be for such  technology in the timeless landscape of the Cornish coast?

The official name of the facility is GCHQ Composite Signals Organisation Station Morwenstow: it is a government listening station.

Its eeriness is exacerbated for me by its resonance with memories from childhood days of passing a similar site at Goonhilly Downs in the south of the county on a day when fog had drifted in from the sea and where the white “golfballs” that housed the apparatus appeared and disappeared in the mist.

The information provided about the Cornish station suggests it is an altogether prosaic place. It is about listening into conversations, monitoring communications. In the world of espionage, it has no more glamour than George Smiley in the novels of John Le Carré. Yet whatever the dull realities of the daily work of the staff at the station, there is a touch of the apocalyptic about the place, a quality of fear that probably owes more to a child listening to adults talking than to contemporary concerns about world politics.

In the 2020s, when the biggest threat to security is small groups of religious extremists, it is hard now to imagine the sense of fear felt in the 1960s. Nevil Shute’s novel “On the Beach”, with its grim depiction of the final days of humanity in a world made uninhabitable by a nuclear war, seems more a work of science fiction than one rooted in the very real sentiments of the times in which it was published. Nuclear war seemed a real possibility to the extent that the government distributed pamphlets advising people on how to cope after an attack.

Perhaps the stories we heard were not true, but in our minds Goonhilly Downs was the station that would tell us that a war was about to commence, that an attack was about to begin, that our world was about to end. Even if it was not true, we would probably have still believed the rumours, still seen the place as the harbinger of our doom.

Is it possible that there are children who travel the road out of Cheltenham or along the road in North Cornwall and look across the buildings and are filled with a similar fear? Do adults talk about GCHQ listening for signs of devastating attacks? A quick Internet search would bring reassurance. Had we had Google in the 1960s, life might have been much happier.