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Trig point

This Freedom of Information request asks for information in relation to trig point TQ47/T371 - Aero Engine Testing Beds.

Request for information - Ref No: FOI221067


Thank you for your email of 3 February 2022, requesting information from Ordnance Survey in accordance with the Freedom of Information Act (FOIA) 2000, as set out in the extract below:

“Information on Trig Point TQ47/T371 - Aero Engine Testing Beds. I am doing some research into my local history and discovered that there was a trig point on an Engine Testing Bed with the reference above and in the attached image from your legacy trig point data. I am requesting extracts from the office & field copies of the surveyors logbooks that may help me identify the owner and use of this structure. I would like to know the owners of the building, the date the trig point was established (pre-1950) from the computation year. Also anything that may help with determining the function of the structure. From the location of the trig point it appears it may have been on the roof of the building but was destroyed on 9/85 though the building still appears to exist from Google Street View & Google Earth as well as personal observation.. If there are any pictures or sketches in the file copies of these would be useful as well. I am happy to accept the results in electronic form. PDF or TIFF if possible”

Our response

I confirm that Ordnance Survey does not hold the information you have requested.

However, under the duty to provide information and assistance in accordance with section 16 of FOIA, we can provide the following information which may assist you in this matter.

The majority of Triangulation Station Office files are now held by The National Archives (TNA). It would appear that the file for Triangulation Station TQ47/T371 (Aero Engine) is held by TNA, and is available for you to order direct from TNA, at the link here: Triangulation (Trig) Station number TQ/47/T371 or 51/47/T371. Trig name: Aero Engine... | The National Archives

You may also find the following general information on our website useful:

Historical map archives (

OS-Net | Ordnance Survey

Internal review

Your enquiry has been processed according to the Freedom of Information Act (FOIA) 2000. If you are unhappy with our response, you may request an internal review with our Internal Review Officer by contacting them, within two months of receipt of our final response to your Freedom of Information (FOI) request, as follows:

Internal Review Officer
Customer Service Centre
Ordnance Survey
Adanac Drive
SO16 0AS

Contact us via our FoI form

Please include the reference number above. You may request an internal review where you believe Ordnance Survey has:

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