One QF 5.25" Mk II gun was installed at Macquarie Battery in Christison Park, Vaucluse, Sydney in early 1945 as the first of three proposed guns. It was located in the south east corner of Christison Park near the Macquarie Lighthouse.

The QF 5.25" Mk II gun had been developed for use in the dual role of a coastal defence gun and an anti-aircraft gun. That first gun at Macquarie Battery had initially been installed at South Head and then Cape Banks to develop and test a portable mounting for use in forward areas. The Macquarie Battery was not fully installed or operational before the war ended and the other two guns were never installed, although a 1956 aerial photo clearly shows that all three concrete round gun emplacements had been built. All sign of the gun emplacements had disappeared by about 1970.


Photo:- “1956 AUSIMAGE © Jacobs Group (Australia) Pty Ltd”

The three gun emplacements can be seen at the bottom right of Christison Park


Photo:- “1956 AUSIMAGE © Jacobs Group (Australia) Pty Ltd”

Closeup view of the three gun emplacements in 1956



On 27 September 2018, an article in the Sydney Morning Herald featured the story of what appeared to be a tunnel entrance in the cliff below the Macquarie Lighthouse. The tunnel opening had been discovered by the use of a drone. It showed a small concrete opening about 150 feet down from the top of the cliff. Despite the fact that it is not far from the former Macquarie Battery, it is believed that this would have been a searchlight emplacement in support of the Signal Battery about 450 metres further north long the cliff coastline. There is a file in National Archives titled "Coast Defence projects: installation of searchlight and engine room emplacements at 5.25" CA/AA battery at Christison Park, N.S.W."

There was a vertical access shaft 120 feet high to access the 60 foot long tunnel to the searchlight opening in the cliff face. Steel ladders were used in the vertical shaft for access. In 1948 two boys climbed down the 120 foot vertical shaft (some newspaper reports said it was 60 feet deep) and accessed the searchlight opening in the cliff face. One of the boys attempted to descend down the cliff from the opening on a rope and had to be rescued by Police.

Well known Professor of Physics at Sydney University, Harry Messel, received permission from the Australian Army in about 1955 to do cosmic ray research in the 60 foot long searchlight tunnel. He wanted to find out the effect of cosmic rays through rock and was using photographic plates that had been especially imported from overseas after being exposed to radiation. These plates were in the tunnel and it was reported in newspaper articles that his experiments were ruined by vandals. Professor Messel apparently had part of the tunnel widened to fit his experiments. He installed two electromagnets weighing 25 tons, a cosmic ray spectrometer, a number of highly sensitive geiger counters, automatic cameras and a cloud chamber. The Professor had originally planned to build a 50 foot deep laboratory in the Sydney University grounds in 1954 however he found the use of the tunnel near Macquarie Lighthouse an easier option in 1955. It is believed by some that some of Professor Messel's equipment may still be in the tunnel.

Archaeological Reports of the Lighthouse Reserve state that the searchlight tunnel’s vertical shaft entrance was filled in some time in the 1970s.

Drone footage taken by Macquarie University in about September 2018 shows the tunnel entrance. Michael Rampe, the Senior Learning Designer at Macquarie University, said that the tunnel entrance had been brought to their attention by the Sydney Harbour Federation Trust whilst they were working on a 3D Imaging Project with the Trust. There are similar searchlight positions further along South Head as well as on North Head.

The concrete roof and a steel girder which has collapsed can be seen. On the right side inside the tunnel there are electrical cables visible and a small circular mounting point can be seen to the right side of the opening. 


Screenshot:- Macquarie University

The Searchlight emplacement for Signal Battery. A 3D Image of the
searchlight entrance can be seen on this Macquarie University site.


Photo:- “1956 AUSIMAGE © Jacobs Group (Australia) Pty Ltd”

The tunnel is inline with the smaller concrete building above
the two concrete buildings to the east of the lighthouse


The entrance to the tunnel (via the vertical shaft) is believed to have been via the smaller concrete building slightly north of the two concrete buildings located to the east of the lighthouse, about 60 feet away from the cliff's edge as seen in the above 1956 aerial photo. The smaller of the two buildings (western side) had disappeared by 1970.

There are documents in the National Archives of Australia relating to “Accesss by the Army to the Lighthouse Reserve”, and also another relating to Professor Messel’s research in the tunnel “Macquarie Lighthouse – electricity supply to underground laboratory”. A search of the term "Christison Park" in the NAA database also finds 19 results mostly to do with the WWII occupation of the park. In one of the digitised files, the Minister for the Army, Cyril Chambers, wrote to Alderman A.H. Hood, the Mayor of Vaucluse in November 1947 and advised that the former military Command Post which had formed part of the artillery installations in the park, and had not been fully completed when the war ended, would not be removed and could be made available to the Council, if desired for use as a dressing room for players using the area. If the council did not want it for that purpose the Army would clean it and secure it. Another letter stated that the Command Post had actually been made available to the Vaucluse Council on 11 July 1947 for use as a dressing shed.

Another letter in the same file, dated 19 August 1947 refers to a number of Army huts that remained in the park area. The Army advised they wanted to retain Hut No. 15 and that Hut Nos. 10, 11 and 12 were surplus to Army requirements and were being handed over to the Commonwealth Disposals Commission for disposal.



Greg McPherson contacted me on 21 July 2021 and told me that he and a friend spent considerable time in the tunnel probably around 1976. They descended the cliffs to do so. Greg stated that the only access (that ever appeared to exist) to the horizontal section of tunnel in the cliff face was via another tunnel that actually goes down a shaft on ladders from the tunnel about half way back along the horizontal section on its left hand side looking from outside. Greg said that the shaft was flooded with water. They tried unsuccessfully to drain the water using hoses to siphon the water over the cliff. The hoses did siphon, but there was way too much water for two kids to deal with.



I'd like to thank Greg McPherson, Michael Rampe, David Patrick and Graham McKenzie-Smith for their assistance with this web page.



"The Unit Guide - The Australian Army 1939 - 1945 Volume 3, Artillery, Air Defence and Engineer Units", pages 141/142.

"First pictures of secret tunnel in cliff face below Macquarie Lighthouse", Sydney Morning Herald, 27 September 2018.

"Secret tunnel in cliff face below Sydney's Macquarie Lighthouse 4K" - YouTube Video

"World War 2 Tunnel Sydney" YouTube video

"Tunnel/Bunker on Cliff Face under Macquarie Lighthouse" YouTube video

NAA File - DEF20574A MACQUARIE LIGHTHOUSE Specification for erection of battery observation post. 24 February
1938. [Box 71], 1938

"Atom Research in Cliff Face", Sydney Morning Herald, 1 May 1955


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This page first produced 13 October 2018

This page last updated 01 September 2021