Sir William Richard Joseph Cook, KCB FRS (10 April 1905 – 16 September 1987) was a British civil servant and mathematician.

In 1947 he joined the Royal Naval Scientific Service, serving as its chief from 1950 to 1954, when he became deputy head of the Weapons Group of the newly created United Kingdom Atomic Energy Authority (UKAEA).

Cook led the project which corrected this, enabling the rockets to be deployed in 1940, with the first battery under Sandys' command, in time to support the air defence of Britain during the Second World War.

Cook then turned to the study of missile guidance mechanisms for the British Liquid Oxygen-Petrol / Guided Aerial Projectile (LOP/GAP) liquid-propellant rocket.

[4] Funding for the Rocket Propulsion Establishment was niggardly, and in 1947 the Chief of the Royal Naval Scientific Service (CRNSS), Frederick Brundrett, recruited Cook as his Director of Physical Research.

In 1950, Brundrett became Deputy Chief Scientific Adviser to the Ministry of Defence to Sir Henry Tizard, and Cook succeeded him as CRNSS.

[6] Tizard retired soon after the 1951 election that returned Winston Churchill's Conservative Party to office, and was succeeded by Sir John Cockcroft.

But Cockcroft was also the director of the Atomic Energy Research Establishment at Harwell, Oxfordshire, and found himself unable to devote sufficient time to both roles.

[7] This task would fall most heavily on the shoulders of Sir William Penney, who was appointed the head of the Weapons Group of the newly created United Kingdom Atomic Energy Authority (UKAEA).

[17] On 1 February 1958, Cook became the UKAEA's Member for Engineering and Production vice Sir Christopher Hinton, who had left to become chairman of the Central Electricity Generating Board.

In the wake of an inquiry by Lord Fleck, production was separated from the UKAEA's Industry Group in July 1959, and Cook became Member for Development and Engineering.

In addition, under the 1958 US–UK Mutual Defence Agreement, the Royal Navy received access to Pressurized Water Reactor (PWR) technology used in US nuclear submarines.

This was a turbulent time for the Ministry, with tight budgetary constraints leading to heated debates over procurement of new weapons systems, none more so than the BAC TSR-2, which was eventually cancelled.

Cook was involved in negotiations with the French, and later German and Italian governments, to build a replacement, which eventually saw service with the RAF as the Panavia Tornado.

Cook then served as the Chief Scientific Adviser to the Ministry of Defence from 1966 until 1970, when he retired from the civil service, although he chaired nuclear safety committees until 1981.

[20] In 1967, the Prime Minister, Harold Wilson sent Cook to brief the French military attaché in London, Colonel André Thoulouze, on the British hydrogen bomb project.

The French hydrogen bomb project was stalled, and Wilson hoped that providing some assistance might influence the President of France, Charles de Gaulle, to approve the accession of the UK to the European Communities.

[23] After Rolls-Royce went bankrupt in 1970, the Secretary of State for Defence, Lord Carrington, asked Cook to chair a committee to determine whether the development of the RB211 jet engine should be continued.