Sir Alan Lloyd Hodgkin OM KBE FRS[1] (5 February 1914 – 20 December 1998) was an English physiologist and biophysicist who shared the 1963 Nobel Prize in Physiology or Medicine with Andrew Huxley and John Eccles.

At the age of 15, he helped Wilfred Backhouse Alexander with surveys of heronries and later, at Gresham's School, he overlapped and spent a lot of time with David Lack.

[10] Between school and college, he spent May 1932 at the Freshwater Biological Station at Wray Castle based on a recommendation of his future Director of Studies at Trinity, Carl Pantin.

[19] During his studies, Hodgkin, who described himself as "having been brought up as a supporter of the British Labour Party"[20] was friends with communists[21] and actively participated in the distribution of anti-war pamphlets.

[30] During that year he also spent time at the Woods Hole Marine Biological Laboratory where he was introduced to the squid giant axon,[31] which ended up being the model system with which he conducted most of the research that eventually led to his Nobel Prize.

[32] Working with single nerve fibres from shore crabs and squids, he showed that the conduction rate was much faster in seawater than in oil, providing strong evidence for the local circuit theory.

His first post was at the Royal Aircraft Establishment where he worked on issues in aviation medicine, such as oxygen supply for pilots at high altitudes and the decompression sickness caused by nitrogen bubbles coming out of the blood.

[37] In February 1940 he transferred to the Telecommunications Research Establishment (TRE) where he worked on the development of centimetric radar, including the design of the village Inn AGLT airborne gun-laying system.

He was a member of E.G. Bowen's group in St Athan in South Wales and lived in a local guest house together with John Pringle and Robert Hanbury Brown.

In February and March 1944, he visited the MIT Radiation Laboratory to help foster the interchange of information on developments in radar between Britain and America.

[40] As the Allied Forces' invasion of France and their continued advance towards Germany in autumn 1944 suggested an end of the war in the foreseeable future, Hodgkin started to plan his return to a career in research at Cambridge.

They proposed that the characteristic shape of the action potential is caused by changes in the selective permeability of the membrane for different ions, specifically sodium, potassium, and chloride.

A model that relies on a set of differential equations and describes each component of an excitable cell as an electrical element was in good agreement with their empirical measurements.

Confirmation of ion channels came with the development of the patch clamp leading to a Nobel prize in 1991 for Erwin Neher and Bert Sakmann, and in 2003 for Roderick MacKinnon.

Together with Richard Keynes he demonstrated that in addition to the changes in permeability that lead to an action potential, there is a secretory mechanism that ejects sodium and absorbs potassium against the electrochemical gradients.

It was only two years later that Hodgkin, Huxley, and Eccles were finally awarded the Prize "for their discoveries concerning the ionic mechanisms involved in excitation and inhibition in the peripheral and central portions of the nerve cell membrane".

Around this time he also ended his experiments on nerve at the Plymouth Marine Laboratory and switched his focus to visual research which he could do in Cambridge with the help of others while serving as president of the Royal Society.

He also held additional administrative posts such as Chancellor, University of Leicester, from 1971 to 1984 A portrait of Hodgkin by Michael Noakes hangs in Trinity College's collection.