Distinguished psychoanalyst and social scientist Isabel Menzies Lyth, from Iffley, in Oxford, who made a major contribution to the field of psychotherapy, has died aged 90.

She was one of the pioneering figures among those, including John Bowlby, Eric Trist and Wilfrid Bion, who founded the Tavistock Institute of Human Relations in London in 1947.

Born in Fife in 1917, she was proud of her origins as the daughter of a minister in the Church of Scotland - a democratic organisation, she said.

Mrs Menzies Lyth gained a first in economics and psychology at St Andrew's University, where she then became a lecturer in economics. She worked for the War Office during the Second World War, helping with work on psychological testing methods to help select potential officers.

After the work she became an expert in psychoanalysis, with specialist expertise in the organisation of groups, especially in the health service.

She came to Oxford in 1975 when she married Oliver Lyth, an Oxford psychoanalyst.

They moved to Iffley, where they continued to practise.

Mr Lyth died in 1981, but Mrs Menzies Lyth continued her work as a psychoanalyst and teacher for counsellors, psychotherapists and NHS mental health staff. She also led a University of the Third Age group studying psychology.

Mrs Menzies Lyth also consulted for the Cotswold Community, a residential school for adolescents, the staff of a rehabilitation ward at Littlemore Hospital, local child guidance clinics and nurses on the regional course in psychodynamic practice.

Her friend Dr Peter Agulnik said: "Isabel was dogged and brave, showing great fortitude in her last days, and ever commanding respect."