Dr Colin Johnston

Consultant Endocrinologist


Specialises in

  • Thyroid disorders including thyroid nodules
  • Pituitary disorders
  • Endocrine disorders including adrenal and sex hormones
  • Diabetes
  • Chronic Fatigue Syndrome/ME

Also available for:

Virtual consultations:

I did my clinical Training in London at St George's, King's College and Hammersmith hospitals. Then completing four years research training in diabetes at Kings College hospital and Seattle, USA.

I was appointed as a Consultant Physician with a specialist interest in Diabetes and Endocrinology at St Albans and Hemel Hempstead in 1989, establishing departments in both hospitals with a national reputation. These merged with Watford into West hospitals Trust where I was Medical Director from 2009-2013. Continue with out-patient clinics in Diabetes, Endocrinology and Chronic Fatigue /ME at St Albans.

I specialise in all aspects of Diabetes and Endocrinology. I was part of the Bariatric service at Spire. I established a joint pituitary clinic at St Albans. I am the clinical lead for diagnosis and therapy for CFS/ME for all of Hertfordshire.

Currently I see personally about 500 new referrals and nearly 1,000 follow up appointments per year. I score very highly in patient satisfaction surveys.

I am the specialty for Diabetes and Endocrinology in the North Thames Clinical Research Network promoting high quality clinical research. I currently the local lead investigator in three studies (1 diabetes and 2 endocrinology).

Throughout my career I have had major clinical management roles locally and nationally being the clinical lead for the Department, the Division of Medicine and eventually as Medical Director. Nationally through the Society of Endocrinology and Diabetes UK. Throughout I have championed high quality, responsive, clinical care.


General Medical Council Number: C2383859

Treatment information

Some of the principal treatments carried out by Dr Colin Johnston at Spire include:

Endocrinology and diabetes

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Important information about COVID-19 tests

COVID-19 testing or antibody tests are not available as a standalone service at Spire Harpenden Hospital.


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Additional information

Endocrinology and diabetes mellitus
Thyroid disease
Pituitary disease

MA / University of Cambridge / 1974
Master of the Arts

MB BCh / University of Cambridge / 1977
Bachelor of Medicine

MRCP / Royal College of Physicians / 1980
Member of the Royal College of Physicians

MD / University of Cambridge / 1985
Doctor of Medicine

FRCP / College of Physicians London / 1992
Fellow of the Royal College of Physicians

Professional memberships

Diabetes UK

Society for Endocrinology

British Thyroid Association

Pituitary Foundation

BACME(British Association of CFS/ME)

Professional leadership

Previous Medical Director of West Herts Trust.
Served on the clinical committees of Diabetes UK and Society of Endocrinology
Currently specialty lead for Diabetes and Endocrinology for North Thames Research Network
Clinical lead for CFS/ME for Hertfordshire

Consultant Physician, Diabetes and Endocrinology, West Hertfordshire Hospitals NHS Trust

North Thames Clinical Research Network

I am now semi-retired from the NHS which allows me more time with less stress to continue with my clinical work being still the main provider of Diabetes and Endocrine services at St Albans and promoting better understanding and treatment for CFS/ME across all of Hertfordshire.

Telephone 0800 585 112
Private secretary Jane Wilson
Private secretary telephone 01582 460 129