Report - - Collyweston explosives storage area (ESA), June 2019 | Military Sites | 28DaysLater.co.uk

Report - Collyweston explosives storage area (ESA), June 2019


28DL Full Member
28DL Full Member
So, there I was out on the bike heading on the fish & chip run up to Matlock Bath when I spied an interesting set of quarries on the A47. Finding the nearest layby, I dug out the OS map to see if I could find out a bit about them. What the map revealed though, looked far more interesting. In some woodland all but a mile away was something that screamed “interesting military site”. With any thoughts of quarries put to rest, it took all of a minute to find the place. Being so close to RAF Wittering, and having no prior knowledge of the area, I approached the area with caution and spent a while observing and prowling around the perimeter – obviously a disused site with plenty of graffiti – but better safe than sorry. Of course, in hindsight, that wasn’t really necessary as the site has been documented to death and back as well as being used for raves.

There’s lots of information about this site, but I’ve tried to bring together what I can from various sources, reports and books to try and give as full a picture as I can without making it a laborious effort. So, onto a bit of history first: I’ve included some broader background to the neighbouring RAF Wittering as it’s important (IMHO) since without a bit of a “deep dive” it’s easy to jump to wrong conclusions (as some folk have) about what the Collyweston site was used for.

The Collyweston explosives storage area (ESA) was built around 1955 [1] as a remote munitions storage site for the nearby RAF Wittering. It is not shown on the 1950s Ordnance Survey map (but that doesn't mean that it wasn't there when the surveys were done). On the 1970 survey, a demarcated area is shown within Collyweston Great Wood, which just happens to be the same shape and size as that shown in detail on today's survey!
OS maps - 1970 and 2019 (Medium) (Small).png

OS maps showing the Collyweston ESA from 1970 (lower) and 2019 (upper).​

RAF Wittering, in the late 1950s was Bomber Command’s main V-bomber nuclear strike base, home to 49 Squadron [2,3] consisting of nuclear-capable Vickers Valiants. This period of time was also when ‘Project E’ was ongoing: this was an agreement between the UK and the USA whereby the USA loaned the UK a number of nuclear weapons whilst the UK’s development programme accelerated. Weapons loaned under Project E had to be kept under the custody of their US guardians, and were located at sites including RAF Honington, RAF Marham and RAF Waddington [3]. The loan initially consisted of 64 Mk7 ‘Thor’ open pit fission weapons (multiple yield between 8 and 61 kiltonnes [4]), primarily for RAF Canberra bombers, and 75 Mk5 open pit fission weapons (multiple yield between 6 and 120 kilotonnes [5]) destined for the V-bomber squadrons.

RAF Wittering was not part of Project E, rather it stored domestically-produced nuclear warheads. This included the first British-produced hydrogen bomb, codenamed “Grapple Y”, with a design yield of 1 megaton. Infamously, on the 26th February 1958, the somewhat unstable “Grapple Y” ended up in a ditch on the side of the A1 as the truck carrying it to RAF Wittering from Aldermaston failed to make it up a hill in Wansford during a blizzard, grappling for traction and skidding off the road [2]. Luckily, “Grapple Y” was undamaged and Northern Cambridgeshire wasn’t annihilated by the biggest nuclear bomb the British ever built: its yield turned out to be 3 megatonnes [6] when detonated over Christmas Island on April 28th 1958. The fissile core stores at RAF Wittering are now disused and, rather entertainingly, are Grade II* listed buildings [7]. Nuclear weapons were never stored at the Collyweston ESA.

What is visible at Collyweston ESA suggests that four types of weapon were stored here [1,8]:
  • 1000lb high explosive bombs;
  • 68 mm SNEB rockets;
  • BL755 cluster bombs;
  • ‘unspecified’ high explosive ordnance from RAF (USAF) Lakenheath.
1000lb bombs
The RAF used to rely heavily on these weapons: the Mk 1 and Mk2 devices were 570lbs in weight [8]. These bombs were maintained at Collyweston, in buildings similar to that shown below [8].
1000lb bomb store.gif

1000lb bomb maintenance building, taken from [8].​

68mm SNEB rockets
The SNEB (Societe Nouvelle des Etablissements Edgar Brand) rocket was an unguided 68mm air to ground weapon [9] manufactured by TDA Armements of France. Capable of being fitted with 7 different types of warhead, these were stored at Collyweston in buildings of the type shown below [8].

68mm SNEB rocket store.gif

68mm SNEB rocket store, taken from [8].​

BL755 cluster bombs
These weapons came into active service in 1972 and were used by offensive support and attack aircraft. Each 600lb warhead carried 147 small bomblets, which dropped over a wide area. This was a domestically-produced weapon by Hunting Engineering in Ampthill, Bedfordshire [8,10]. BL755s were stored in ‘Dutch Barns’, as shown below. Of everything on the site today, these are worth taking care with as they’re made almost entirely of (now ageing) asbestos.

BL755 cluster bomb stores.gif

'Dutch Barns' for BL755 cluster bombs - note asbestos construction. Taken from [8].​

Unspecified USAF ordnance
The buildings used to store the US ordnance are, in my view, some of the most interesting on the site. They appear to be Freloc Igloos [11], as shown below. Freloc Igloos are designed to be naturally ventilated [11] and have internal volume of 735 cubic metres.

Freloc Igloo - isometric.png

Isometric view of Freloc Igloo, taken from [11].

Freloc Igloo.png

Section views of Freloc Igloos, taken from [11].

Freloc igloos - old.gif

The Freloc Igloos prior to, ahem, repainting. Taken from [8].​

The echoes inside these things are brilliant – not quite up to the insides of cooling towers – but not far off. Despite a fair bit of digging, I’ve been unable to find any concrete information about the 'unspecified US ordnance'. It would be easy to speculate, given the nature of the enclosures, that high explosive used to detonate fission weapons could have been stored here, but there is no evidence to corroborate that. Of course, it could just have been plain old high explosive!

The Collyweston ESA was, I think, decommissioned in 1996. The site has been used for a number of raves over the years [1], with the resulting debris and litter still very much in evidence. Shame folk can’t clear up their crap after themselves… Metal thieves have helped themselves to all the 3-phase armoured cable, leaving the PVC sheaths scattered over the site. There’s a good deal of graffiti – some of which is pretty decent and worth looking out for. It also looks like local Airsoft enthusiasts use the place quite regularly as there are loads of pellets in some of the buildings – rather them than me playing wargames and crawling around in areas with a fuckload of asbestos…

And finally, after getting somewhat distracted by bits of history on nuclear weapons and high explosives, photos! Firstly, in and around the 1000lb bomb maintenance buildings:

CRW_1214-01 (Medium).jpg

CRW_1215-01 (Medium).jpg

CRW_1216-01 (Medium).jpg

CRW_1217-01 (Medium).jpg

CRW_1220-01 (Medium).jpg

CRW_1224-01 (Medium).jpg

CRW_1226-01 (Medium).jpg

CRW_1218-01 (Medium).jpg
CRW_1221-01 (Medium).jpg

CRW_1225-01 (Medium).jpg
Now onto the 'Dutch Barns' - there's quite a lot of these left, but equally many must have been demolished as well. They're in varying states of repair...
CRW_1232-01 (Medium).jpg

CRW_1231-01 (Medium).jpg

Now, time to scramble over a few earth banks to the SNEB rocket stores:

CRW_1240-01 (Medium).jpg
CRW_1243-01 (Medium).jpg
CRW_1242-01 (Medium).jpg

And now the Freloc Igloos - very easy to spend quite a lot of time in this sector of the site:

CRW_1244-01 (Medium).jpg
CRW_1246-01 (Medium).jpg
CRW_1247-01 (Medium).jpg
CRW_1252-01 (Medium).jpg
CRW_1253-01 (Medium).jpg

And finally, on the way out of the site a quick stop in a small brick building that turns out to have a pump in it. At a guess, it could be the firewater supply pump - although the building it sits in is below site grade and comes with the risk of flooding... D'oh... Oh, and a final piece of art to leave you with.

CRW_1261-01 (Medium).jpg

CRW_1262-01 (Medium).jpg

A thoroughly enjoyable, and very unexpected, break in a good ride. Luckily, the chipp(ies) in Matlock stay open all day so lunch was had, albeit a bit late. Thank you for looking!

1. https://sync-below.com/collyweston-esa-part-one/
2. Rimmer A., “Between heaven and hell”, Lulu.com 2012, ISBN 129120928X
3. Oskins J. & Dobson J., “The Nuclear Weapons Chronicles”, Lulu.com 2017, ISBN 1365915484
4. https://en.wikipedia.org/wiki/Mark_7_nuclear_bomb
5. https://en.wikipedia.org/wiki/Mark_5_nuclear_bomb
6. https://en.wikipedia.org/wiki/Operation_Grapple#Grapple_Y
7. https://historicengland.org.uk/listing/the-list/list-entry/1402763
8. http://www.bunkertours.co.uk/royal_air_force.htm
9. https://en.wikipedia.org/wiki/SNEB
10. https://www.globalsecurity.org/military/world/europe/hunting.htm
11. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/198281/C6_Edt4_FINAL.pdf


28DL Full Member
28DL Full Member
Blimey - the place has changed a bit since then, then. Different era, different armaments I guess. Thank you for serving (RAF?).