In his most recent lecture on the implementation aspects of his Final Report, Lord Justice Jackson turned the spotlight on the costs associated with expert witnesses. Particularly interesting were his comments in relation to the ‘concurrent evidence procedure’, or ‘hot-tubbing’, as it is wryly termed by lawyers.

Inspired by an Australian technique, hot-tubbing involves a radical departure from the current norm of experts examined in the witness box by barristers, with opposing evidence often not heard until weeks later. By contrast, in the hot-tub, experts give their evidence together in the form of a discussion chaired by the judge. Barristers can ask questions as well as the judge, but crucially, experts can also challenge one another on their views by asking direct questions.

Whereas under the current system, an expert may be able to gloss over or omit information that does not support their view - in the knowledge that, ultimately, the expert knows more about their specialist field than the barrister questioning them - that will become much more difficult in the new discussion forum.

Experts will also need to be fully familiar with the subject matter, which will become much more important than how good they are at performing in the witness box. The expert who does not fully understand the subject will have nowhere to hide, and it will be far harder to present opinion as fact. Jackson notes that a pilot of this concurrent evidence technique in Manchester - originally in the Mercantile Court and Technology and Construction Court, now extended to the Manchester Chancery Court - has suggested that it is quicker, better for experts, cheaper in terms of trial time and cost, and makes it easier for judges to understand complex technical evidence.

It is understood to be broadly popular with lawyers, clients and experts themselves. No surprise, then, that Jackson suggests that a practice note could be in place by next October to allow civil judges to order experts into the hot-tub; a development that could potentially have a far-reaching impact on trial strategy and the use of expert evidence.

But, as Jackson himself acknowledges, there is one factor that could put the brakes on this new advance: judicial resources. The Court of Appeal judge points out that concurrent evidence ‘should not be undertaken unless the judge has time to master the expert reports properly’. In the hot-tub, there will be much more focus on the judge himself, and their own understanding of the points in dispute. A judge who has thoroughly familiarised himself with the deeply technical evidence at hand will be able to greatly assist the progress of the case, by quickly getting to the bottom of the key aspects on which there is disagreement. But a judge who has not undertaken such a detailed examination - possibly due to lack of time - may well be less inclined to use the new approach, in which they will be expected to take such a pro-active role.

The hot-tub technique may be desired by parties, lawyers and experts, but ultimately its success will depend on the attitude, enthusiasm, and resources of those on the bench.

Rachel Rothwell is a freelance journalist and editor of Litigation Funding

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