Mary – Teresa specialises in professional discipline and health and safety with a particular focus on the healthcare sector. She is instructed in some of the highest profile, complex and sensitive cases on the instructions of defence organisations, including the Royal College of Nursing and the Royal College of Midwives, and regulatory bodies, including the General Dental Council, the Care Quality Commission and the Nursing and Midwifery Council. Her experience covers the acute sector, the community, care homes and prisons.

Mary -Teresa has extensive experience during the COVID19 pandemic in remote hearings including contested final hearings.


  • Butterworths Law Prize, The Queen’s University of Belfast
  • Middle Temple Benefactors Law Scholarship
  • Lady Margaret Templeman award, Middle Temple


Mary-Teresa is quick thinking and solution focused. Mary-Teresa’s analytical skills are exceptional.  Legal 500 2023 Professional Disciplinary and Regulatory Law Tier 1

A forensic and tenacious advocate. She is meticulous, thorough and puts her all into every case. She is indefatigable in her pursuit of obtaining the best outcome for her clients. Legal 500 2022 Professional Disciplinary and Regulatory Law Tier 1 

“Methodical and unwavering with great attention to detail.” Legal 500 2020 Professional Disciplinary and Regulatory Law Tier 1

“Methodical and unwavering with great attention to detail.” Legal 500 2019 Professional Disciplinary and Regulatory Law

“Courteous, fair and very tough – always well prepared presenting or defending.”  Legal 500 2018 Professional Disciplinary and Regulatory Law 

“Her arguments are succinct and pithy.” Legal 500 2017 Professional Disciplinary and Regulatory Law  


  • Panel B Health and Safety and Environmental Law
  •  Legal Advisor to the General Pharmaceutical Council
  • Clerk to the British Association for Counselling and Psychotherapy


  • Certificate of Academic Legal Studies, the Queen’s University of Belfast
  •  Ph.D, the Queen’s University of Belfast
  •  B.Sc, The University of Aston in Birmingham

Professional Memberships

  • ARDL
  • HSLA

Public Access

Undertakes Public Access work

General Medical Council v Dr Kumar

Representing an orthopaedic surgeon charged with dishonestly failing to disclose, in response to an express question on an application form, that he was being investigated by the GMC for sexually motivated conduct towards a patient, an investigation which was subsequently the subject of findings and for which he was suspended for 12 months. A combined hearing took place remotely over three days via Skype for business of the review of the suspension order and the substantive hearing of the dishonesty charges. The dishonesty charges were admitted. The MPTS found misconduct but that the doctor showed significant insight into his dishonest conduct and found impairment solely on the ground of public interest and imposed a suspension order for two months with no review.

AZJ Healthcare Services Limited v Care Quality Commission

Successfully resisted an appeal on the instruction of the CQC against a decision of the CQC to cancel the registration of a provider of healthcare services. The hearing involved five witnesses and took place remotely via Kinley over three days. The First Tier Tribunal found breaches of regulations 12(1) (safe care and treatment) and 17(1) (good governance) of the Health and Social Care Act 2008 (Regulated Activities) Regulations 2014 and regulations 12(1), (2) and (3) (statement of purpose) of CQC (Registration) Regulations 2009.

NMC v Helen Lockett

Represented Helen Lockett, former Director of Operations and Executive Nurse at Liverpool Community NHS Trust, over 94 days. Allegations of misconduct, including concealing concerns, bullying and the downgrading of risks, arose in the context of upheaval in the NHS including unprecedented cutbacks in funding in the NHS, increased demand for health care services in the community and national issues in the recruitment and retention of district nurses.

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NMC v Emma Short

Representing Emma Short, the Service Manager for an Inpatient Unit for people with learning disabilities where, in 2013, Connor Sparrowhawk had an epileptic fit in the bath a died. After an inquest in 2015 found that his death was partly due to neglect, Mrs Short faced grave charges, including contributing to or causing the death of the young man. However, following the demonstration of systemic institutional failings during a forty-five day hearing, no charges were found proved.

GDC v Julie Elston and Kimberley Craig

Instructed by the GDC in a complex dispute that concerned significant irregularities in record keeping by a dentist in sole practice and a Registered Dental Care Professional she had employed. An NHS England review identified significant issues, including allegations that Ms Elston had signed blank prescription forms and had prescribed an antibiotic for herself. The fifteen day hearing raised challenging issues of evidence. All but one of the charges against Ms Elston were proved and she was suspended for six months with a review whilst Ms Craig was reprimanded.

NMC v Professor Sir George Castledine

Instructed by the NMC in these widely-reported proceedings. Whilst working at the Institute of Ageing and Health in the West Midlands the registrant was asked by members of her family to provide bereavement counselling to a recently widowed woman in her eighties. The registrant was found to have acted in both a sexually motivated way and a financially motivated way and was struck off.

The Carer – 17 December 2020

21st December 2020

Making Arrangements for Care Home Residents to Visit Family and Friends Over Christmas – Risks Associated with COVID-19

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Visitors to Care Homes Over Christmas

10th December 2020

Mary-Teresa Deignan has written a piece for The Carer looking at the Department of Health and Social Care’s most recent guidance on visitors to care homes during Covid-19.

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TGC Welcomes New Tenants

7th October 2020

Temple Garden Chambers is delighted to announce that Mary-Teresa Deignan has accepted an invitation to join chambers. Mary-Teresa specialises in professional discipline and health and safety with a particular focus on the healthcare sector.

TGC is also delighted to announce that Paul Erdunast and Harry Peto  have accepted invitations to join chambers after successfully completing pupillage.