Snowdon’s ‘secret’ WWII experiments

What on earth was going on?

A rudimentary train service ran for the first three years of the war. As the conflict intensified many things were requestioned for the war effort and the summit hotel was one of these. The military took over the summit buildings in 1942. Trippers could still walk up to the summit, however every encouragement was made to keep them away from the summit hotel and barbed wire was put around the building to prevent any unwanted visitors.

According to the Snowdonia National Park website, “From 1942-1945 it was requisitioned by the Ministry of Supply for experimental radio work, then by the Air Ministry for radar development. Next, the Admiralty carried out secret work here and finally the Army had use of it.”

The summit cafe in 1980. During WW2 barbed wire would have surrounded the building (see pic at bottom)
Copyright Author’s collection

A brief background to the research and the men involved

At least three men are known to have worked at the summit 1944 to January 1945. A fourth un-named man, formerly a batsman, became the person who waited upon the men as they worked on their projects at the summit. The three men became famous physicians later in life, and they were Fred Hoyle, Hermann Bondi and Cyril Domb.

Cyril Domb met Fred Hoyle in July 1941 at the Admiralty Signal Establishment. Domb was 20 and Holye then 26. Hoyle was in charge of the Theoretical Group in radar research. The research work was then being conducted together with astrophysicist Thomas Gold at a farm cottage near Dunsfold in Surrey. In 1942 Bondi became number two in Hoyle’s team, and Gold, Bondi and Domb worked at Dunsfold until 1944.

Soon after they left Dunsfold Hoyle used Snowdon Summit for experiments with the Air Ministry to test short-wave propagation at high altitude, which involved sending signals from Snowdon to a reciever in the Mourne Mountains of Northern Ireland.

The old summit station 1st August 1980. A large nissen hut built across the tracks here in 1944 housed the 2 army Lister generators. Copyright Author’s collection

The work undertaken at the summit

The success of the Air Ministry work led Hoyle to suggest using Snowdon summit to conduct new experiments for the Admiralty. Snowdon was ideal for its height and proximity to the sea, and the rack railway for transporting the equipment and generators, not forgetting a regular supply of food and other essentials. The generators were Listers, obtained from the army. The sophisicated equipment gave Holye the ability to send radio waves across around 60 miles of sea to the Aeroplane and Armament Experimental Establishment near Aberporth in South Wales, 70 miles distant.

The admiralty’s ‘secret work’ entailed the use of magnetron valves and other electrical equipment supplied by GEC’s Wembley laboratories. The magnetron valves and their associated equipment were set up within the summit hotel itself. These constituted powerful transmitters and receivers initially set up to find ways to spot enemy submarines from the air and to determine the extent to which enemy aircraft could be detected despite jamming. Later it was used to analyse radar’s ability to cope under certain weather conditions, especially over water.

Hoyle knew that his colleague Herman Bondi loved mountains so Hoyle dispatched him to the summit of Snowdon to oversee and set up the new project. One result of Bondi’s residence at the summit of Snowdon was that the observation of how electrons behaved in the magnetrons. Bondi developed a theory describing their quantum nature, which were greatly contributory towards the then new developing theories of rotating fluids and stellar/planetary accretion.

The ‘truck’ & No.6 do a training run to Rocky Valley on 27 May 1980. Its clear Hoyle & Co used the passenger carriages as the ‘truck’ was not built until 1950. Copyright Author’s collection

On the first day Hoyle and Domb travelled to Llanberis with every intention of catching the 4.15pm train to the summit. They missed it and Hoyle told Domb they’d have to walk to the summit. Unlike Hoyle, Domb was not used to this kind of thing and was appalled at the prospect of climbing a mountain! Upon driving both Bondi and Domb back to Llanberis after their regular update meetings, Hoyle appeared very adept at missing the train, often forcing both men to make their own way to the summit!

The experiments began in June 1944 with a large aerial. Sources say it was 11.5m in diameter. I think this must be an error for it is suggested the aerial was inside the hotel. If so it must have been set to an angle in order to fit inside the building but then I do not see how it would have worked placed on a near horizontal level. It clearly must have been smaller – 11½ft rather than 11.5m. The tests were intended to last until October. It was decided to extend them into the winter to study the effects of wave clutter, for which the rougher winter weather was ideal. Essentials and food were brought up by the railway in preparation for the onset of winter. In January 1945 the experiments ended altogether.

The summit cafe: The remains of the fencing that surrounded the building during wartime is evident. The fencing lasted to the late sixties. The aerial dish on the roof is probably linked to the BBC’s ‘A Night on the Mountain’ programme which was broadcast live from the summit in the mid 1950’s. This image can be found on the Delcampe website

Work at the summit ends – and sensitive data is lost!

The one problem was the secret equipment could not be left at the summit. As the railway was not running. It was decided each man should carry a magnetron for these were the most sensitive components from the project and their capture by the enemy would have repercussions for Britain. The less sensitive equipment would have to wait until the railway recommenced services in the spring.

The men set down the mountain with the magnetrons strapped to their backs. As they descended the weather took a turn for the worse. Severe gales blew and one of the team lost his rucksack containing the important documents about the project. Admiralty were furious at this loss and ordered Hermann to find them. He returned to Snowdon with 35 commandos prepared to search for the sensitive documents. Many hours of searching amongst the cliffs and gullies near Clogwyn eventually retrieved the papers, still intact in the rucksack.

The Army took over the summit hotel for just a few months to the end of the war in August 1945. What they used it for is not known. Soon after war finished the railway was allowed to recommence substantial passenger services to the summit. The railway was in a bad condition and there was hardly any money available. It is mentioned in a couple of sources that the company was left with no choice but to burn old army boots in place of coal as it had no money to purchase the latter for its locomotives!

Fred Hoyle & Hermann Bondi. Images from Wikipedia

Fred Hoyle: (1915-2001)
Left the admiralty in 1945 to focus on his work in Astrophysics. He was a leading proponent of the view that the Big Bang was something that never happened. Along with Chandra Wickramasinghe, Hoyle developed new theories on the origin of life in the universe.

Hermann Bondi: (1919 – 2005)
A brilliant mathematician and cosmologist, Bondi’s major work sought to refine the principles of general relativity, especially with regards to gravitational radiation. He, Gold and Hoyle developed their theory of the steady-state universe, meaning the big bang did not occur and the universe has neither beginning nor end.

Cyril Domb: (1920 – )
Domb is best known for his work concerning phase transitions. He left the Admiralty in 1946 to undertake further studies at Cambridge for a PHD. He lives in Israel and is the only surviving member of the group who conducted tests at Snowdon summit.

Hoyle, Bondi (and Gold) had very similar interests – life, the universe and the lack of a big bang. They loved the mountains and were all good climbers. Additionally Bondi was a renowed skier, whilst Hoyle was an enthusiastic Munro bagger.

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