Born at Merstham, Surrey on 9 January 1899,[1] Jefferis was educated at Tonbridge School and Royal Military Academy, Woolwich.
He had accordingly gone down the railway line and joined Brigadier Morgan’s Brigade; but the Norwegians had categorically refused to allow him to carry out any demolitions.
Although the casualties had not been so great as from shell fire, the moral effect of seeing the aircraft coming, of being unable to take cover, of being able to observe the bomb dropping, and of the terrific explosion, had been overwhelming.
Picking up a sergeant and two privates, he had succeeded in making his way back to Andalsnes; and on the way he had managed to blow up the girders of two bridges on the German side.
None had hit, but the immunity of a ship under such conditions could only be, in Major Jefferis’s opinion, a matter of time, and he calculated that his life would probably not be more than three days.
The general conclusion which he (the Prime Minister) drew from Major Jefferis’s account was that it was quite impossible for land forces to withstand complete air superiority of the kind which the Germans had enjoyed in Norway.
[9] For his service in Norway, Jefferis was awarded the Norwegian War Cross with sword,[10] and mentioned in dispatches for his efforts in the withdrawal from Lillehammer.
When MIR was combined with other hush-hush elements to form the SOE, Jefferis' unit was not included and it instead became a department in the Ministry of Defence; the only unit of the Minister of Defence (The Prime Minister, Winston Churchill) and was known as "MD1", ultimately based in a house called "The Firs" in Whitchurch near Aylesbury in Buckinghamshire England.
[13] The unit was responsible for the design, development and production of a number of unique special forces and regular munitions during the Second World War.
Through the application of the Squash head and HEAT technology they had a role in the development and production of Lt-Col Stewart Blacker's Blacker Bombard, the PIAT (Blacker's smaller version of the bombard) matched to a hollow charge warhead, Hedgehog (effectively an adaption of the Bombard spigot mortar principle working with the Navy's Directorate of Miscellaneous Weapons Development) and tank variants including the AVRE with its "Flying Dustbin" 230mm Petard spigot mortar,[14] and a bridge-laying tank.
[16] Jefferis' development of the hollow charge led ultimately to the same design being used, after refinement by James Chadwick, in the core of the plutonium bomb dropped on Nagasaki.
[2][24][25] As an ADC, Jefferis took part in George VI's funeral, and Queen Elizabeth II's Coronation Procession.
In 1938, he built a 7-ton yacht at Aldershot called Prelude with another Royal Engineer officer and they sailed successfully both before and after the war.