Frederick Lindemann at Chartwell

Signatures in Churchill's visitors book at Chartwell, a National Trust property in Kent

Professor Frederick Alexander Lindemann, 1st Viscount Cherwell was an English physicist who became an influential scientific adviser to the British government and to Winston Churchill personally.

Lindemann was born on 5 April 1886 at Baden-Baden. He was the second of three sons of Adolphus Frederick Lindemann, whose family was of Catholic French Alsatian origin, and his American wife, Olga Noble. Lindemann's father emigrated to Britain in his twenties and later became a naturalised British citizen.

Lindemann gained his doctorate at the Physikalisch-Chemisches Institut in Berlin in 1910. A vegetarian all his life, he neither smoked nor drank alcohol. He was an excellent pianist and first-class tennis player, and competed at Wimbledon. In March 1915 he joined the Royal Aircraft Factory at Farnborough, the chief centre of experimental aviation in Britain.

In 1919 he was elected Professor of Experimental Philosophy (physics) in the University of Oxford, heading the Clarendon Laboratory. He was held in high regard by such scientists as Albert Einstein, Max Planck and Ernest Rutherford. He was elected a fellow of the Royal Society in 1920.

In 1921 he met Churchill - the beginning of a lifelong friendship. Despite Lindemann's right-wing social and political views, which included eugenics, he was among the first to recognise the danger posed by Hitler and the inadequacy of British air defence.

In 1939 he became personal assistant to Churchill and head of his statistical section. He continued the same work when Churchill became Prime Minister. Lindemann was made a peer in 1941 with the title of Baron Cherwell of Oxford.

Cherwell was a master at lucidly presenting highly complicated matters with the greatest economy of words. He actively supported experiments in new weapons of every sort. Navigational aids were improved, including the invention of H2S, which gave a radar picture of the terrain below to the navigators of the Pathfinder night bombers.

Sometimes seen as arrogant, Cherwell's judgement, like that of many others, sometimes also went astray. One example is area bombing, which did not stop German war production.

With the fall of the Churchill administration in 1945 Cherwell returned to Oxford. In October 1951 he reluctantly joined Churchill's cabinet, again as Paymaster-General.

He died in his sleep aged 71 at Christ Church on the morning of 3 July 1957.