Blue Plaques

LONSDALE, Kathleen (1903–1971)

Plaque erected in 2021 by English Heritage at 19 Colenso Road, Seven Kings, London, IG2 7AG, London Borough of Redbridge

All images © English Heritage


Crystallographer and peace campaigner


Philanthropy and Reform, Science


Dame KATHLEEN LONSDALE 1903–1971 Crystallographer and peace campaigner lived here in early life



Dame Kathleen Lonsdale conducted pioneering research into the movement of atoms within crystals, and campaigned extensively for international peace. She was the first female professor at University College London (UCL), and one of the first women to be appointed a member of the Royal Society. Her blue plaque commemorates her childhood home at 19 Colenso Road in Seven Kings, where she lived from 1911 until 1927.

Black and white photograph of Dame Kathleen Lonsdale as a young woman, wearing academic gowns
Dame Kathleen Lonsdale as a young woman in her graduation gowns. She won a scholarship to Bedford College at the young age of 16 and subsequently gained her doctorate from UCL © Courtesy of the Lonsdale family


Kathleen Lonsdale (née Yardley) was born in Ireland, but moved to England with her family while still young. She lived at 19 Colenso Road, then in Essex, from the age of 8 until 24. This vital and formative period of her life encompassed her school days, university studies, and her first research job. At Ilford County High School, she attended classes in physics, chemistry and higher mathematics in the boys’ school, because the girls were not usually taught these subjects. With special permission and a County Major Scholarship, she entered Bedford College for Women, part of the University of London, at the unusually young age of 16. She first read mathematics, but at the end of her first year switched to physics. Having come top in the University of London BSc list in 1922, she was invited by one of her examiners, Sir William H Bragg, the founder of X-ray crystallography, to join his research team at UCL, which moved to the Royal Institution (RI) in 1923.

As well as being the background to her formative years as a scientist, Lonsdale’s time at 19 Colenso Road also helped shape her pacifist views. During the air raids of the First World War, Lonsdale witnessed a Zeppelin being shot down in flames. She remembered her mother crying, saying ‘Oh, the poor men, the poor men.’ When Lonsdale and her siblings contested that they were Germans, their mother replied, ‘Yes, I know, but they are boys.’ It was from this point on that Lonsdale questioned the moral justification of war.


Lonsdale worked at Leeds University’s department of physics in the late 1920s, having moved to the city with her husband, Thomas Jackson Lonsdale. In 1928 she determined the structure of hexamethylbenzene, the first aromatic compound to be defined by X-ray diffraction, and so proved conclusively that carbon atoms in the benzene nucleus are hexagonal and flat – an important milestone in organic chemistry. She was also the first to use Fourier spectral methods while solving the structure of hexachlorobenzene.

She gave birth to her first of three children during this time, and at the end of 1931 her former professor, William Bragg, obtained a grant that was used to provide her with domestic help. This enabled her return to a post at the RI in London researching X-ray crystallography. Her subsequent work on the thermal motion of atoms within crystals earned her election to the Royal Society in 1945, making her one of the first two women –alongside biochemist Marjory Stephenson – to be so honoured.

In 1946 Lonsdale became Reader in Crystallography at UCL, then Professor of Chemistry (the first female professor in any discipline at the college) and head of the Department of Crystallography from 1949 until 1968. Her work on crystal structures was also applied to practical medical benefit in the treatment of endemic kidney and bladder stones.

Black and white photograph of Dame Kathleen Lonsdale in a laboratory
Lonsdale in the laboratory at UCL in 1948, when she was Professor of Chemistry. The photograph was published in an article in Picture Post titled ‘Have Women Justified the Vote?’ © Charles Hewitt/Picture Post/Hulton Archive/Getty Images


Lonsdale believed passionately in encouraging and supporting women to have a family and a professional scientific career. In a lecture towards the end of her life she said:

Sir Lawrence Bragg once . . . described the life of a University Professor as similar to that of a queen bee, nurtured, tended and cared for because she has only one function in life. Nothing could be farther from the life lived by the average professional woman.

Along with her husband, Lonsdale became a Quaker in 1935 and, as such, an absolute pacifist. Her refusal on principle to register for civil defence duties during the Second World War, or to pay the subsequent fine, led to a one-month incarceration in Holloway Prison in 1943, which instigated her work for penal reform after the War. 

Lonsdale was devoted to the cause of international peace, and deeply concerned with ethics and the role of science in society. She was president of the British section of the Women’s International League for Peace and Freedom, and was active in discussions surrounding the applications and dangers of nuclear physics. In addition to her prolific output of scientific articles and papers, she wrote many lectures and papers on subjects connected with peace, prisons and religion, including a book, Is Peace Possible? (1957).

Lonsdale died of cancer at University College Hospital on 1 April 1971, and a meeting to remember her life was held at the Quaker centre, Friends’ House, on 20 May 1971.

Nearby Blue Plaques

Nearby Blue Plaques

'step into englands story