Mathematician, linguist and classical scholar, John Clemow was a natural choice for the Technical Staff during the Second World War and he solved a problem with the 6-pounder anti-tank gun that General Bernard Montgomery had complained “could not hit a barn door”. Later, his expertise on guided weapons took him to the US and then into British industry.

Winning a scholarship to St John’s College, Cambridge, in 1930, he gained a first in the mathematical tripos to become a Fellow of the Institute of Mathematics. He joined the Territorial Army in 1934 and as an artillery officer began specialising in gun design and manufacture.

He taught at the Military College of Science in Bury, Lancashire, till 1944, when Montgomery demanded someone to solve the 6-pounder problem. In 1945 he became chief design officer at the Armament Research and Development Establishment in Fort Halstead, Kent.

He was sent to Germany in 1947 to find out everything possible about the German wartime guided weapons programme, with particular emphasis on the V2 rocket system. Utilising his fluent German, he was engaged in interviewing Nazi scientists until leaving for the US Army’s Fort Bliss in Texas and New Mexico for formal training on guided weapons development and techniques.

His mathematical and scientific skills soon put him in a leading position and on promotion to lieutenant-colonel he was seconded to the Royal Aircraft Establishment at Farnborough, Hampshire, as project manager for the six guided-weapons systems then under development. By 1951 he was a colonel and assistant director for guided weapon projects in the Ministry of Supply. When the air-to-air guided missile Blue Sky ran into technical difficulties in 1953, he was seconded to the Fairey Aviation Company and brought the project to a successful conclusion for operations with the RAF within two years.

Promoted to brigadier in 1953, he returned to the Ministry of Supply as Director, Guided Weapon Projects, with a staff of some 60 officers and the substantial sum of £20 million for the industrial development, manufacture and trials of guided weapons for all three Armed Services. The First Sea Lord, Admiral Earl Mountbatten, made him responsible for resolving outstanding problems with the Seaslug missile for the Royal Navy, authorising him to use his name in the event of any obstruction in Whitehall.

Established as a leading expert on guided weapons in Britain, in 1957 Clemow was invited to join Vickers Armstrong as chief engineer (weapons). He left the Army and remained at Vickers till 1961 while the successful Vigilant anti-tank missile was developed as a Vickers private venture, resulting in the sale of 12,000 to the British Army and 6,000 for export. In this period he also published technical books on short-range guided weapons and on missile guidance. On the formation of the British Aircraft Corporation, he left Vickers to join the General Electric Company at Stanmore, Middlesex.

While he really wanted to confine himself to civil work at GEC, he was persuaded to take the positions of engineering and technical director. This involved bringing together six units into a single working unit embracing underwater weapons, sonar, military communications, digital and analogue computers, data links, servo-mechanisms, weapons guidance, airborne radar, gun control, scientific and communications satellites and test equipment.

From 1966 until his retirement in 1976 Clemow worked for the Science Research Council as chief physicist. In this capacity he pursued his interest in high-energy nuclear physics. In later life he evinced some disappointment at the bureaucracy of the council and was not sorry to retire from it to enjoy what he regarded as a more fruitful time of classical scholarship and reading.

The son of a Royal Navy dockyard shipwright of Cornish origin, John Clemow was born in Sheerness, Kent, but moved to Glasgow when his father was posted to the dockyard on the Clyde. His interest in mathematics already manifest, he also began collecting books of poetry and history. On his father’s transfer to Sheerness, the family returned to England and his father bought a smallholding on the Isle of Sheppey. The young Clemow obtained a grammar school place, using his holidays to visit Germany and become fluent in the language. Later he became variously proficient in Latin, Greek, Ancient Greek, Italian, French, Norwegian, Russian, Arabic, Hebrew, Chinese and Sanskrit.

His annual “Pendulum Letters”, originating with undergraduate colleagues from Cambridge, continued well into his nineties, their erudite observations providing a lasting testament to the breadth and depth of his knowledge of art, literature, music, history, law and politics.

A convert to Roman Catholicism, he was deeply versed in the world’s religions and worked as a volunteer for Amnesty International for more than ten years and on indexing books for the Royal National Institute for the Blind.

His wife, Dorothy, predeceased him. He is survived by a daughter.

Brigadier John Clemow, Director, Guided Weapon Projects, Ministry of Supply, 1953-57, was born on November 9, 1911. He died on November 17, 2008, aged 97