Until 2015, Marsh was the senior consultant neurosurgeon at the Atkinson Morley Wing at
St George's Hospital, south London, one of the country's largest specialist brain surgery units. He specialised in operating on the brain under
local anaesthetic and was the subject of a major
BBC documentary
Your Life in Their Hands in 2004, which won the
Royal Television Society Gold Medal. He has been working with neurosurgeons in the
former Soviet Union, mainly in
Ukraine since 1992 and his work there was the subject of the BBC
Storyville film
The English Surgeon from 2007. This won an Emmy award in 2010 for best science documentary.
Other work He has a particular interest in the influence of hospital buildings and design on patient outcomes and staff morale; he has broadcast and lectured widely on this subject. He states that one of his proudest achievements has been the creation of a balcony garden outside the two neurosurgical wards at St. George's Hospital. In 2023 he co-founded with Dr. Rachel Clarke the charity Hospice Ukraine, which aims to help
palliative care doctors and nurses in Ukraine. He has been working with medical colleagues in Ukraine since 1992, and has continued to visit since the
Russian invasion in February 2022.
Writing His memoir
Do No Harm: Stories of Life, Death and Brain Surgery was published in 2014. According to
The Economist, this memoir is "so elegantly written it is little wonder some say that in Mr Marsh neurosurgery has found its Boswell". It has been translated into 37 languages. In 2017, Marsh published
Admissions: Life as a Brain Surgeon, a second memoir with
Weidenfeld & Nicolson, an imprint of
Orion. In 2022 he published
And Finally with
Jonathan Cape, in which he describes his transition from being a doctor to being a patient with
cancer. Both books were
Sunday Times best sellers. He writes regularly for the
New Statesman magazine and has written for
The Guardian, the
Financial Times,
The Times,
The New York Times,
The Sunday Times and the online Ukrainian newspaper
Ukrainska Pravda. ==Other Radio and television==