Summary

Blue Streak underground silo, 1958-60.

Source: Historic England

Details

The earthwork remains of the foundations for the experimental underground launcher facility (U1) lie 600m to the south-east of Greymare Hill in the bottom of the valley of a small stream called the Cheese Burn.

The excavated hole for the underground launching facility’s foundations is roughly circular in shape and measures about 32m in diameter, the northern side has a well-formed curved plan and a good profile. Around its lip, close to where the stream enters, are traces of concrete blocks that were used to line the excavation. Running approximately north to south across the centre of the hole are three rows of boards, these measure 1ft 2in x 2in (34cm x 5cm) and are fixed to vertical posts 3 3/4-in (9cm) square. They are joined together with well-finished lap joints and bolts, and are further strengthened by U-shaped cleats hammered between the joints. To the west some of the boards have been removed. The boards are thought to represent shuttering put in place to support the sides of the hole during excavation. To the west of the hole a by-pass channel was dug to divert the Cheese Burn around the excavation. At its western end are the remains of a sluice comprising two concrete walls into which are set two vertical 2 x 4-inch (5 x 10 cm) steel channels into which blocking boards could be inserted into the 2.99m wide gap. Beyond the sluice an earthwork channel is visible along the southern valley scarp and to the south of the hole. To the north of this sluice the original line of the stream was straightened and its sides lined with rocks, some cemented into place. The base of the stream is very hard and may have been surfaced in asphalt. Close to the hole is another sluice constructed in a similar manner to that described above, although here the gap is 3.06m.

Extent of scheduling
On the south side this is defined by the top of the scarp of the by-pass channel; to the west it then follows the west side of the artificial channel as far as the westernmost sluice. From here the boundary follows the northern side of the Cheese Burn and then the upper edge of the scarp defining the excavation. It follows this scarp edge to c.50m to the east of the excavation where the southern bypass joins the stream. At this point it crosses the stream to join the upper edge of the by-pass channel scarp. To the north of the scheduled area there are a series of spoil mounds up to 2m in height which do not form part of the scheduling as their archaeological potential is considered to be limited.

Source: Historic England

Reasons for Scheduling

The 1958-9 Blue Streak underground silo is scheduled for the following principal reasons:
* Rarity: considered to be the free world's first in-silo launch weapon system concept and an essential and integral part of a unique British Cold War rocket establishment believed to be the sole survivor of its type in the western world;
* Survival: significant earthwork and buried remains survive at this site which illustrate one component of the rocket test facility;
* Potential: the physical remains will enhance our detailed understanding of the design and development process of Britain's nuclear deterrent as well as serving as a tangible and evocative symbol of Britain’s aspirations to superpower status;
* Historic interest: although the work on the missile silo was cancelled along with the Blue Streak programme in April 1960, the technology directly influenced subsequent United States' designs including the Titan II missile silos, which remained operational until 1987. For this it has international technological claims;
* Group value: as part of a single phase, grand scheme site conceived for a single rocket programme, the relationship of each site to the others and the wider landscape adds group value and enhances the national importance of the whole;
* Period: the peril from the threat of mutually assured nuclear destruction, which characterised the Cold War period is inherent in the remains of the Spadeadam rocket facility in the most tangible and evocative fashion.

Source: Historic England

Sources

Books and journals
Stumpf, D K, Titan II: A History of a Cold War Missile Programme, (2000)
'Flight' in Blue Streak helps Titan, , Vol. 78, (1961), 889
Cocroft, W D, 'Prospero: The Journal of British Rocketry and Nuclear History' in The Spadeadam Blue Streak Underground Launcher Facility U1, (2006)
Other
Tuck, C & Cocroft W D, Spadeadam Rocket Establishment, Cumbria, 2004,

Source: Historic England