Jonathan Felix Ashmore FRS FMedSci FRSB (born 1948)^[1] is a British physicist and Bernard Katz Professor of Biophysics at University College London.^[10]

He is the son of Rosalie Crutchley who played Madame Defarge in A Tale of Two Cities.

Ashmore was educated at Westminster School^[1] as a Queen's Scholar. He studied mathematics and physics at the University of Sussex^[2] followed by a PhD in theoretical physics in 1971 supervised by Tom Kibble at Imperial College London where his research investigated quantum field theory.^[7]

After a short postdoctoral research fellowship supervised by Abdus Salam^[8] at the International Centre for Theoretical Physics in Trieste, Italy he retrained as a physiologist at UCL, gaining a Master of Science degree in 1974^[2] which led to work with Paul Fatt and Gertrude Falk^[11] between 1974 and 1977 in the Biophysics Department.

Ashmore was appointed a Lecturer in Physiology at the University of Bristol in 1983 and promoted to Reader in 1988, before moving back to UCL in 1993.^[8][2]

Ashmore has worked on dissecting the cellular mechanisms of hearing by studying the organ of Corti in the mammalian cochlea^[12] especially the guinea pig (Cavia porcellus).^[13][14] This structure in the inner ear increases the selectivity and sensitivity of our hearing through an in-built cochlear amplifier.^[15] He showed that specialised cells known as outer hair cells are responsible for this unique function.^[15][16][17]

In response to sound, outer hair cells lengthen then shorten through a process controlled and powered by the flow of electrically charged molecules such as potassium ions.^[18] This contraction propagates and amplifies sound, and he was the first to capture it on film during his Rock Around the Clock Hair Cell video.^[10][15]

His work has combined biophysical methods – including the patch clamp technique usually applied to membrane proteins – with confocal microscopy imaging and computational modelling to expand our knowledge of hearing at the molecular and cellular level. His findings are helping to unravel the nature and origins of hearing-related conditions like deafness and tinnitus.^[3][15]

His research has been funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and the Medical Research Council (MRC)^[19] and he has supervised several doctoral students to completion including Dan Jagger.^[9]

Ashmore is the son of renowned theatre director and actor Peter Ashmore and actress Rosalie Crutchley.^[21] Aged seven, Ashmore played Joe in the 1955 film A Kid for Two Farthings, adapted from the novel by Wolf Mankowitz.^[22] Through his mother, Ashmore is descended from the 1st Earl of Leicester and his second wife, Lady Anne Amelia Keppel, a descendant of Charles II of England.