RAF Marks Castle (Trevescan Cliff) Chain Home Low CHL 17A

A comprehensive site plan of RAF Mark's Castle. An index to the buildings will be added soon. There are a number of buildings which have been located by field walks. One interviewee said he remembered two Ops blocks which may now be correct having located building No 21. Although I do not think there was a second Gantry. Three hut bases also located No's 6,17 and 18 These are seen in the original "distant" photo of the gantry and then right on the right hand edge can be seen an earth mound, consistant with the site of large rubble present in exactly the correct place today. Next to the "Mound" structure is the base of the standby hut (Generator). Still to locate is the Anti-aircraft gun location. I am certain when I interview Douglas, the question will be answered. He was a Gunner on site throughout the war.

Numbers 17 & 18 or 21 One of these has now turned out to be the base for the early transmitter housed in a nissen hut, photo shown lower down this page.


From original Air Ministry drawing


Revised 19 July 1943 13713


1.T&R Gantry


2.First Aid Shelter


3.Tx Operations Block


4.Rx Operations Block


5.Standby Set Hut


6.General Purpose Hut This location also marks the 1st of two link aeriel masts which


stood some 360 ft high.


7.Interrogation Mast IFF


8.Interrogation Hut IFF


9.Storage Hut


10.Gunners Orderly Room


11.Sleeping Accommodation


12.Sleeping Accommodation


13.Sleeping Accommodation


14.Ordnance Store


15.Sleeping Quarters


16.Gatehouse (Guard Room)


It is known from letters written from RAF Sennen from WAAF Gillie Gilmour with the following excerpt is taken August 1943 “ they have started two new sort of stations here, very secret and very hush hush, hence the enormous amount of WAAF’s turning up. In Jan 2013 I identified these further buildings, some confirmed from a WW2 photograph."


17.Hut base seen in photo


18.Hut base seen in photo


19.Toilet block in present day coast path


20.Hut base this is also the second base for the second of the link aeriel masts.


21.Secondary buried Block

Mark's Castle Operations Block



The same view as photo above in 2012. Both show the Longships Lighthouse

The Gantry plinth looking towards the Operations Block




Mark's Castle Operations Block viewed from Land's End Hotel


How many walkers pass this as they walk the Coast path? It is the remains of the toilet block by the Ops room. Sadly over the winter of 2013-14 with the restoration work to the Coast Path, these remains are now gone.


Concrete bases of the RAF Gunners Nissen huts




Typical Operations Block interior



Recently found in January 2013, the remains of the Guardroom, near the present day Coach park for Land's End.

This part of the Sennen (Skewjack) drawing has the Sennen Cove section in the right hand corner. If you click the picture and then full screen when it opens you will see the entire Sennen Cove set up.










These five drawings relate to the propagation of signals at Marks Castle. More than that I can't tell you.

Supplied by the RAF Museum.







The only accessible building left is the air raid shelter, it transpires that the National Trust do not own the Mark's Castle land. The owners do have positive ideas for the area. Watch this space.

Could this ever become an on site visitors center as others are doing else where?




Once an extremely important part of the defence of Cornwall. Only a handfull of people know of the history here and they tend to be in their seventies to ninties. Memories are failing fast. I had been told that this was National Trust land but in turns out not to be.

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Such an exciting addition to the Mark’s Castle Photo Gallery thanks again to Mu Cook-Martin. This is the early transmitter on the site, housed in a nissen hut. The heart of the site. This is the equipment that she worked on and maintained. Thank you Mu and son David.

A similar Transmitter at RAF Sopley. Slight differences as you can see. RAF RADAR museum curator Chris Moreshead had not seen such a unit in a Nissen Hut.



April 2013

In the original photo's of the Operations block, both show aeriel masts. I was puzzeled as to what thes were for. Chain Home Low A.M.E.S. type 2 had the rotating scanners as seen on the main gantry. I wondered if these were early CHL aeriels or communications. In the last email I received from Mu Cook-Martiin, following a question from me she replied that she remembered the masts. Her husband (also serving in Radar) said that it was a transmitter aeriel, but it was a failure. I was further puzzeled. I spoke to Chris Morshead at RAF Ground defence museum he said that the twin mast set up used for Chain Home was a failure when applied to low level Chain Home Low hence the rotating Gantry came into use. This was experimented firstly at RAF Worth Matravers on the Solent. Another puzzel solved.