A clinician by background with a passion for using evidence to improve care, Professor Leng joined NICE, the National Institute for Health and Care Excellence, in 2001 and became its second CEO on 1 April 2020. In this role she led the development of a new 5 year strategy and set out updated methods and processes to put NICE at the forefront of evaluating new medicines, devices and diagnostics, and deliver dynamic living guidelines for frontline staff.

Her career has covered a breadth of sectors including wider public health, healthcare, education and social care. It has entailed close working with the life science industries, patient organisations, professional societies, academia, plus local and national government across the United Kingdom. She has chaired national and international boards and committees, bringing comprehensive media experience across a range of complex topics.

She is a trustee (previously Chair) of the Guidelines International Network, and has also sat on the boards of the Royal Society of Medicine and the Centre for Ageing Better. IShe was a Commissioner for the recent Global Evidence Commission, aiming to improve the use of evidence in policy-making.