Presenter biographies: M to O

Dr Macnair has worked in a variety of hospital specialities, including anaesthetics and intensive care, respiratory medicine and renal medicine.

She also works as a freelance medical journalist and broadcaster.

Her particular interests include ethical and legal medical problems, end-of-life issues, palliative care and pain control, obesity and weight loss.

Holly Margerison works in the nutrition communications group at the Medical Research Council, Human Nutrition Research Unit.

She works to promote public understanding on the links between nutrition and health with industry, health professionals, academics, community groups and the media. As part of this she gives talks and develops information for schools and community groups.

Dr Marsden is a psychologist and senior lecturer in addictive behaviour at the division of psychological medicine and pyschiatry at the Institute of Psychiatry.

He's also a senior editor of the scientific journal Addiction and a member of the UK Advisory Council on the Misuse of Drugs. His research interests focus on the development and evaluation of treatments for drug and alcohol dependence.

Dr Morris is an GP with a special interest in allergic disorders. He works part-time as a clinical assistant at a specialist NHS allergy clinic in London.

He consults at several allergy clinics in private hospitals and clinics in London and Surrey. His specialist interests include asthma, allergic rhinitis, hay fever, eczema, urticaria and angioedema. He specialises in food allergy and anaphylaxis.

He's a member of the British Society of Allergy and Clinical Immunology and the European Academy of Allergy and Clinical Immunology.

Dr Morse is a GP and an honorary lecturer in general practice at Southampton University.

He works as medical adviser to Clouds House addiction treatment centre and is a founder member of the International Society of Addiction Medicine.