A giant shed used to house airships during the First World War was given Grade II listed status by Culture Minister Barbara Follett today.
The "Beta Shed" at Farnborough Airport, one of only a handful of portable airship hangars to have survived across Europe, is to be protected because of its "unique" history.
The structure was created around 1892-1893 and erected at the Hampshire airbase between 1910 and 1911.
It was used during the war to house airships, or balloons, which provided air observation of German submarines, monitoring threats to shipping, including supply convoys, in the North Sea and the Channel.
The new listed status will provide the shed with enhanced protection against insensitive development.
Ms Follett said: "This is a most unusual and unique building and deserves preservation.
"Only six of these sheds existed at the beginning of the First World War, and this one has housed some truly remarkable examples of British engineering.
"Its links with the development of early aerial reconnaissance is a reminder of a critically important time in Britain's aviation history and it deserves the extra protection that listing brings."
Farnborough was the location of the first airship trials, including the first Sea Scout (SS), but the base was abandoned by the Naval Airship Service because of the expanding aeroplane squadrons there, and the personnel and airships were transferred to Kingsnorth, Kent, which became the airship headquarters.