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Henry Mainwaring

Henry has a mixed common law practice, with both advisory and advocacy elements in the areas of commercial contract law, professional regulation, professional negligence and clinical negligence.


Known for his meticulous preparation, he combines diligent hard work with a keen understanding of the law and a pragmatic, down-to-earth approach. Henry works hard to achieve the quickest and most cost-effective solutions. He lives between London and the Isle of Man; his practice takes him nationwide.


Henry Mainwaring (1)

Henry's Experience

Called in 2001

Public Access Accredited


Barristers in England and Wales are regulated by the Bar Standards Board

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Commercial Contract

With a background in construction/building disputes, Henry has a deep experience of broad spectrum of contractual disputes, including large scale commercial arbitrations before the London Court of Internation Arbitration (where in 2021 he represented the owner of the largest solar power station in Africa, and became one of only 0.5% of individuals who had successfully challenged the right of an arbitrator to continue sitting on the Tribunal panel).

As well as providing litigation advice and advocacy, Henry frequently advises on and drafts contracts for clients, including the insurance, parking and sports industries. In the context of litigation, his work ethic is to identify at an early stage the needs of the client and to help bring the matter to a speedy and commercially sensible conclusion through the courts or, if appropriate, Alternative Dispute Resolution.

Professional Regulation & Professional Negligence

Over many years, Henry has obtained wide experience of professional regulatory matters and has acted for many respondents before regulatory bodies, including the:

  • Solicitors’ Disciplinary Tribunal
  • Chartered Insurance Institute of Costs Lawyers
  • General Medical Council
  • Nursing and Midwifery Council

Typically, Henry will defend professionals facing serious disciplinary charges which have the potential to end their careers. He has represented professionals facing allegations of fraud, theft, sexual misconduct, gross negligence, and clinical competency before tribunals of first instance, and within the context of appeals to the High Court. He has a very successful record in such matters and comes highly recommended.

Henry also advises in relation to partnership disputes, having acted successfully in numerous disputes and contentious situations over the years. He is a qualified mediator and has undertaken work in numerous successful mediations, both as counsel and as mediator. The professional regulatory aspect of Henry’s practice dovetails with the work which he undertakes in the field of negligence more generally.

Clinical Negligence, Personal Injury & Inquests

Head of the The Barrister Group's Inquests group, Henry is regularly instructed by the largest unions to represent their members at inquests and public inquiries. He has a successful track record of advising and appearing in clinical negligence claims, as well as serious personal injury claims more generally, including industrial accidents. Henry is often instructed by both insurers and families to protect their interests in the context of fatal accidents.


Henry frequently appears in the Senior Courts Costs Office as an advocate at detailed assessments. His broad experience obtained over 20 years means that he is well placed to understand the underlying litigation and, therefore, to achieve very good results for his clients.

  • Commercial Bar Association

  • Association for Regulatory and Disciplinary Lawyers
Privacy Policy

1. This is a privacy notice that describes how, why and for how long I will process or keep your personal data in accordance with the General Data Protection Regulation (‘GDPR’).
2. The GDPR governs how an individual’s personal data is used, and your rights in relation to that data.
3.  I, Henry Mainwaring, have been instructed by you or your litigation friend (usually a parent), through your solicitor or agent, or via the Bar Pro Bono Unit.
4.  It is necessary for me to process your personal data in order for me to provide you with legal services, for example:

  • Advise on the prospects of litigation;
  • Advise on the value of your claim;
  • Representation at a court hearing;
  • Representation at trial;
  • Advise, review or comment on legal issues or evidence.

5. Processing means anything done to data such as: recording, organising, adapting, altering, copying, consulting, transmitting, combining, erasing or storing it.

6.The processing for the purposes listed above will take place in accordance with either Article 6(1)(a) GDPR or Article 6(1)(b) GDPR, depending on how you instructed me.

7. If you have instructed me on a direct access basis, or engaged a solicitor (or legal agent), to assist you in bringing or defending a claim then the processing is necessary to perform a contract to which you are a party (Article 6(1)(b) GDPR). To give effect to that contract (i.e. to bring a claim) it is necessary for me to process your personal data for litigation purposes.

8. If I am assisting you on a pro bono basis, it will be necessary for me to seek your consent to be able to represent you (Article 6(1)(a) GDPR). In this scenario, you will be sent a consent form.

Recipients of your data

9.  I may also be required to share your data with others, depending on the nature of your case. This may include:

(i)  Courts and other tribunals to whom documents are presented;

(ii) Your solicitors, or agent representing you, through whom I have been instructed;

(iii) Potential witnesses, experts and other persons involved in the case;

(iv) Solicitors, barristers, or other legal representatives;

(v) Ombudsman and regulatory authorities;

(vi) Education and examining bodies; and

(vii) Current, past or prospective employers.

Special Categories of Data

10.  In some cases I will have been given your personal data that is within the ‘special categories’ of data described in GDPR Article 9(1). For example, personal data that reveals your race, ethnicity, sexual preferences, political or religious beliefs, trade union membership or health. There are also restrictions for processing information regarding criminal convictions.

11. This type of personal data will only be processed where it is necessary in order to represent you in your legal claim, or advise on the prospects of a legal claim.


12. I will retain your personal data for no longer than is necessary, and where it is possible, I will anonymise your data.

13. How long your personal data is kept will depend on a number of factors. The retention period will be reviewed when the service I am providing you with is complete. However in general, I am obliged by the Bar Code of Conduct to retain records of my cases, and by HM Revenue and Customs to retain records for 6 years.

14. Once your case has concluded and fees have been paid, I shall retain only the personal data necessary for the following purposes:

(i) The legal and professional obligation to retain information relating to my cases;

(ii) To check for any potential conflict of interests that may arise in the future when I am instructed on other cases;

(iii) For use in the defence of potential complaints, legal proceedings or fee disputes;

(iv) To refer back to in future cases which raise similar legal, factual, or procedural issues.

15. The processing for the purposes listed in paragraph 14 (ii), (iii), and (iv) above, will take place in accordance with Article 6(1)(f) GDPR. That is, for the purposes of legitimate interests that are not outweighed by your interests or fundamental rights and freedoms.

16. The processing for the purposes listed in paragraph 14(i) above, will take place in accordance with Article 6(1)(c) GDPR. That is, the processing is necessary for me to comply with a legal obligation. 

Your Rights

17. Where processing of your personal data was based on your consent (see paragraphs 6 and 8) you have the right to withdraw that consent at any time. This does not affect the lawfulness of the processing based on consent before its withdrawal.

18. Withdrawal of your consent to process such data will most likely mean that I am no longer able to provide you with the legal services you seek.

19. You may request confirmation that your personal data is being processed by me and details about the personal data, the source, the processing, the purposes of the processing, the recipients and the retention period.

20. You may request a copy of your personal data that is being processed by me. You may also request rectification (i.e. correction) where there are inaccuracies in the personal data.

21. You have the right to object, on grounds relating to your particular situation, at any time, to processing of your personal data in paragraph 14 of this privacy notice. Should you object, the processing will only continue where there are compelling legitimate grounds for the processing which override your fundamental rights, freedoms and interests. 

22. Where the processing or retention of your data is necessary for the establishment, exercise or defence of legal claims, it will not be possible to object. 

23. You have the right to request that your personal data is erased where any of the following apply:

(i) The personal data are no longer necessary in relation to the purposes for which they were collected or otherwise processed;

(ii) You withdraw your consent where the basis of processing was based on consent and where there is no other ground for the processing;

(iii) Where your fundamental rights, freedoms and interests override the legitimate interests of processing in paragraph 14;

(iv) The personal data has been unlawfully processed; or

(v) The personal data have to be erased to comply with a legal obligation.

24. You have the right to request that your personal data is restricted from processing, so that it is simply stored, for the following reasons: as an alternative to deletion; so that it can be corrected; for the establishment, exercise or defence of legal claims; to verify if a legitimate ground exists (paragraph 14).

25. Where it is necessary to correct your personal data, or you have requested the restriction or erasure of your personal data, I shall endeavour to contact the recipients of the personal data, unless this involves disproportionate effort. 


26. I take appropriate physical and technical procedures to safeguard your personal data to prevent it from being accidentally lost, used or accessed in an unauthorised way. 

Complaints or Queries

27. If you have any questions regarding this privacy notice, or how I use your personal data please email me: mailto:, or my clerks: telephone 01823 247 247.

28. I shall aim to respond as soon as possible, and within 30 days.

29. You have the right to complain to the Information Commissioner's Office (ICO) if you believe I have not handled your request in an appropriate manner. For information on contacting the ICO please go to:

Henry's Testimonials

Henry Mainwaring is a rarity. He is a man of exceptional intellect and a true gentleman. His thorough preparation, clever approach and client care take him to another level. Very pleased with the result.

Steven Horsley, Partner

Smith & Graham

We were extremely pleased with the work Mr Mainwaring undertook in this case. A telephone conference I had with Counsel immediately prior to the hearing demonstrated Counsel had prepared the case in great detail. Counsel achieved a great result and I was particularly impressed with Counsel's overall conduct of this case. His views were very much endorsed when the papers were returned and I could not fail to notice that the trial bundle had been meticulously tabbed and cross-referenced. To me, as a senior member of a firm of Solicitors, it demonstrated the amount of work Counsel had spent in preparing for the trial in this case.

Jeffrey Palmer

Croftons LLP

Counsel went the "extra mile" that the case required to achieve a very pleasing outcome and we are extremely grateful for Counsel's assistance in this matter [RTA case] given the challenging nature of the brief and case itself. We would certainly be more than happy to instruct Mr Mainwaring again and wished to provide some positive feedback regarding the hard work and the successful result today as we felt that this was truly well deserved.

Joanne Barber

Joanne Barber



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Contact us about working with Henry

If you’d like to work with Henry Mainwaring or any of our other TBG PI & Complex Injury barristers, send us your details and we’ll get back to you.