She became a consultant haematologist in 1985 at the Central Middlesex Hospital in Brent - a relatively deprived part of northwest London - and became Professor of Haemoglobinopathies there in 1997, by which time the hospital had been incorporated into Imperial College London.
In June 2010, Davies became interim Chief Medical Officer for England and was confirmed as the permanent holder of that position the following year - the first woman to hold the post [REF].