UK: Hot Tubbing

Last Updated: 21 April 2010

The Jackson Report on litigation costs included some novelties, for example the concept of "hot tubbing".

Hot tubbing or "concurrent evidence", is a method of giving evidence where both experts give evidence simultaneously and the court or tribunal chairs a discussion between them. Hot tubbing is regularly practised in Australian Courts and international arbitration proceedings, where it is often used after cross-examination.

In his Final Report, Jackson LJ recommended that hot tubbing should be piloted in cases where all parties and the judge agree to it. This has the potential not only to save costs but to improve the quality of court decision making.

How does it work?

Although the format of hot tubbing differs from case to case the basic approach is that experts are sworn in at the same time and the judge chairs a discussion between them. The pre-trial documents (recording the matters upon which the experts agree/disagree) serve as the agenda. Counsel is able to join in the discussion and can put questions to the experts, as and when permitted by the judge. In addition, the experts can put questions to each other.

The theory is that experts are more likely to make concessions and reach a greater degree of agreement in the hot tub than through cross-examination. In the hot tub, experts are more relaxed and can therefore take part in a more constructive discussion.

Experts often answer questions at the same time and so hot tubbing is effective in helping to identify areas where the experts truly disagree. Unlike cross examination, the experts in a hot tub scenario are asked broad questions which generally seem to elicit helpful answers.

Also, as each expert is subject to simultaneous peer scrutiny, the risk of misleading answers is reduced and so any inaccuracies should be picked up immediately. If there is any confusion or uncertainty, the experts can be asked questions straight away to clarify an issue.

Pros and Cons

Hot tubbing has a number of advantages:

  • It saves both time and costs. Instead of counsel turning round to take whispered instructions during cross-examination, counsel can now put his questions to the experts in the hot tub. Both/all experts can then deal with that particular point.
  • Experts can properly help the court to resolve disputes
  • Hot tubbing does away with the "one on one" gladiatorial combat between cross-examining counsel and each expert
  • From the experience of the Australian courts, it would seem that overall, the procedure works well, especially where the experts know and respect each other.

But there are also disadvantages. Where the experts do not know or respect one another's expertise or where there is a suggestion that an expert is not acting in good faith, hot tubbing may not work. Or, time may be wasted as the experts go round in circles or digress from relevant issues. From the practitioner's perspective a concern is loss of control. An expert may lose his concentration and may also lose the fear that he would experience under cross examination. This may lead him to make concessions that he would not make if he was in the box on his own (and would not make if he thought about the question properly). To reduce this risk, experts need to be thoroughly prepared for the hot tub.

If there is no cross examination, as the Jackson report seems to suggest, there is a risk that counsel will not have the opportunity to make all the points that they would like to make, particularly if questions from the advocates are not permitted as part of the process. There is also a risk that key documents might be missed if the advocates cannot bring them to the attention of the court.

Will hot tubbing work for me?

You should consider "hot tubbing" if:

  • You have a strong case and your expert is confident and persuasive (especially where you know he will come across better than the other expert – weak experts can easily be exposed in the hot tub).
  • Your expert has had previous experience of being in the hot tub (especially if his opposite number hasn't).
  • The issues in dispute are complex and you want to give your expert a chance to explain his theories.

Where it comes down to a simple choice between the hot tub or cross examination, it might be best to steer clear of the hot tub where the credibility of your opponent's expert is in issue. Here a tough cross examination will probably be more advantageous.

The extent of hot tubbing in the UK courts will depend on the approach taken by any pilot. This firm intends to become involved in the pilot project so watch this space.

Tim Constable comments – as with the concept of single joint experts, hot tubbing sounds superficially attractive but in reality it is dangerous for the parties – one wrong comment in this notionally relaxed atmosphere could spell doom for an otherwise meritorious case. Consequently, experts will be inclined to clam up which rather defeats the purpose.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on

Click to Login as an existing user or Register so you can print this article.

In association with
Related Topics
Related Articles
Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Registration (you must scroll down to set your data preferences)

Mondaq Ltd requires you to register and provide information that personally identifies you, including your content preferences, for three primary purposes (full details of Mondaq’s use of your personal data can be found in our Privacy and Cookies Notice):

  • To allow you to personalize the Mondaq websites you are visiting to show content ("Content") relevant to your interests.
  • To enable features such as password reminder, news alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our content providers ("Contributors") who contribute Content for free for your use.

Mondaq hopes that our registered users will support us in maintaining our free to view business model by consenting to our use of your personal data as described below.

Mondaq has a "free to view" business model. Our services are paid for by Contributors in exchange for Mondaq providing them with access to information about who accesses their content. Once personal data is transferred to our Contributors they become a data controller of this personal data. They use it to measure the response that their articles are receiving, as a form of market research. They may also use it to provide Mondaq users with information about their products and services.

Details of each Contributor to which your personal data will be transferred is clearly stated within the Content that you access. For full details of how this Contributor will use your personal data, you should review the Contributor’s own Privacy Notice.

Please indicate your preference below:

Yes, I am happy to support Mondaq in maintaining its free to view business model by agreeing to allow Mondaq to share my personal data with Contributors whose Content I access
No, I do not want Mondaq to share my personal data with Contributors

Also please let us know whether you are happy to receive communications promoting products and services offered by Mondaq:

Yes, I am happy to received promotional communications from Mondaq
No, please do not send me promotional communications from Mondaq
Terms & Conditions (the Website) is owned and managed by Mondaq Ltd (Mondaq). Mondaq grants you a non-exclusive, revocable licence to access the Website and associated services, such as the Mondaq News Alerts (Services), subject to and in consideration of your compliance with the following terms and conditions of use (Terms). Your use of the Website and/or Services constitutes your agreement to the Terms. Mondaq may terminate your use of the Website and Services if you are in breach of these Terms or if Mondaq decides to terminate the licence granted hereunder for any reason whatsoever.

Use of

To Use you must be: eighteen (18) years old or over; legally capable of entering into binding contracts; and not in any way prohibited by the applicable law to enter into these Terms in the jurisdiction which you are currently located.

You may use the Website as an unregistered user, however, you are required to register as a user if you wish to read the full text of the Content or to receive the Services.

You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these Terms or with the prior written consent of Mondaq. You may not use electronic or other means to extract details or information from the Content. Nor shall you extract information about users or Contributors in order to offer them any services or products.

In your use of the Website and/or Services you shall: comply with all applicable laws, regulations, directives and legislations which apply to your Use of the Website and/or Services in whatever country you are physically located including without limitation any and all consumer law, export control laws and regulations; provide to us true, correct and accurate information and promptly inform us in the event that any information that you have provided to us changes or becomes inaccurate; notify Mondaq immediately of any circumstances where you have reason to believe that any Intellectual Property Rights or any other rights of any third party may have been infringed; co-operate with reasonable security or other checks or requests for information made by Mondaq from time to time; and at all times be fully liable for the breach of any of these Terms by a third party using your login details to access the Website and/or Services

however, you shall not: do anything likely to impair, interfere with or damage or cause harm or distress to any persons, or the network; do anything that will infringe any Intellectual Property Rights or other rights of Mondaq or any third party; or use the Website, Services and/or Content otherwise than in accordance with these Terms; use any trade marks or service marks of Mondaq or the Contributors, or do anything which may be seen to take unfair advantage of the reputation and goodwill of Mondaq or the Contributors, or the Website, Services and/or Content.

Mondaq reserves the right, in its sole discretion, to take any action that it deems necessary and appropriate in the event it considers that there is a breach or threatened breach of the Terms.

Mondaq’s Rights and Obligations

Unless otherwise expressly set out to the contrary, nothing in these Terms shall serve to transfer from Mondaq to you, any Intellectual Property Rights owned by and/or licensed to Mondaq and all rights, title and interest in and to such Intellectual Property Rights will remain exclusively with Mondaq and/or its licensors.

Mondaq shall use its reasonable endeavours to make the Website and Services available to you at all times, but we cannot guarantee an uninterrupted and fault free service.

Mondaq reserves the right to make changes to the services and/or the Website or part thereof, from time to time, and we may add, remove, modify and/or vary any elements of features and functionalities of the Website or the services.

Mondaq also reserves the right from time to time to monitor your Use of the Website and/or services.


The Content is general information only. It is not intended to constitute legal advice or seek to be the complete and comprehensive statement of the law, nor is it intended to address your specific requirements or provide advice on which reliance should be placed. Mondaq and/or its Contributors and other suppliers make no representations about the suitability of the information contained in the Content for any purpose. All Content provided "as is" without warranty of any kind. Mondaq and/or its Contributors and other suppliers hereby exclude and disclaim all representations, warranties or guarantees with regard to the Content, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. To the maximum extent permitted by law, Mondaq expressly excludes all representations, warranties, obligations, and liabilities arising out of or in connection with all Content. In no event shall Mondaq and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use of the Content or performance of Mondaq’s Services.


Mondaq may alter or amend these Terms by amending them on the Website. By continuing to Use the Services and/or the Website after such amendment, you will be deemed to have accepted any amendment to these Terms.

These Terms shall be governed by and construed in accordance with the laws of England and Wales and you irrevocably submit to the exclusive jurisdiction of the courts of England and Wales to settle any dispute which may arise out of or in connection with these Terms. If you live outside the United Kingdom, English law shall apply only to the extent that English law shall not deprive you of any legal protection accorded in accordance with the law of the place where you are habitually resident ("Local Law"). In the event English law deprives you of any legal protection which is accorded to you under Local Law, then these terms shall be governed by Local Law and any dispute or claim arising out of or in connection with these Terms shall be subject to the non-exclusive jurisdiction of the courts where you are habitually resident.

You may print and keep a copy of these Terms, which form the entire agreement between you and Mondaq and supersede any other communications or advertising in respect of the Service and/or the Website.

No delay in exercising or non-exercise by you and/or Mondaq of any of its rights under or in connection with these Terms shall operate as a waiver or release of each of your or Mondaq’s right. Rather, any such waiver or release must be specifically granted in writing signed by the party granting it.

If any part of these Terms is held unenforceable, that part shall be enforced to the maximum extent permissible so as to give effect to the intent of the parties, and the Terms shall continue in full force and effect.

Mondaq shall not incur any liability to you on account of any loss or damage resulting from any delay or failure to perform all or any part of these Terms if such delay or failure is caused, in whole or in part, by events, occurrences, or causes beyond the control of Mondaq. Such events, occurrences or causes will include, without limitation, acts of God, strikes, lockouts, server and network failure, riots, acts of war, earthquakes, fire and explosions.

By clicking Register you state you have read and agree to our Terms and Conditions