Shadow experts: A secret weapon in complex disputes

The term ‘shadow expert’ recognises their less visible role in the litigation process, as compared to a formal expert witness appointed under Part 35 of the Civil Procedure Rules (CPR 35). Unlike a CPR 35 expert, a shadow expert does not have an overriding duty to the court and their involvement isn’t typically disclosed to the other party.  

Sometimes alternatively known as an ‘expert advisor’ the shadow expert’s role isn’t to testify or produce reports for the court or tribunal, but to provide confidential advice that helps the legal team and client understand and respond to technical and financial issues.  

Shadow experts’ advice must still be honest and realistic, and they must adhere to the applicable ethical standards. However, they’re somewhat freer to play a more significant role in informing case strategy and direction than a formal CPR 35 expert witness. 

Pre-action investigations, advice and strategy  

Shadow or advisory experts are usefully appointed in the investigation stages of a case. They can help the client and legal team understand the key issues as the claims are emerging and inform litigation strategy considerations. A shadow expert can: 

• prepare early analyses and give the legal team a steer on the potential claim value
• provide advice that can impact on whether the claim is brought at all, or whether the strategy may be to try to settle early
• outline the strengths and weaknesses of key liability or causation arguments using technical evidence: for example, whether the work meets the standard of a reasonably competent professional in a negligence case.  

In major cases, the shadow or advisory expert’s early investigatory work can sometimes be substantial. For example, in a large and complex civil fraud matter, a thorough pre-litigation investigation can be necessary prior to launching a claim, and especially where ‘full and frank’ disclosure obligations apply to accompanying without-notice freezing applications. (As in this case: “Litigants that fall foul of the duty to give full and frank disclosure run the risk of their injunctive relief, protecting against the dissipation of assets, being set aside.) 

The expert’s early advice can also be critical in helping to secure third-party funding, by helping to remove some of the uncertainties about quantum of damages, including through scenario modelling. In addition, their work can support strategy considerations, such as which defendants to target based on the evidence against each. 

Pleadings and disclosure  

Once the causes of action have started to take shape and the pleadings are being drafted, shadow or advisory experts can help the legal team: 

• perform further exploratory analysis
• accurately frame the key technical arguments
• identify key supporting evidence
• clarify technical terminology
• further quantify and articulate the claimed damages. 
   

They can also review the other party’s defence to identify areas requiring further investigation and help articulate responses to technical issues to be included in reply submissions.  

During the disclosure phase, shadow or advisory experts can help:

• identify relevant documents  
• review for completeness
• support the client to extract and process key financial data
• formulate disclosure requests.  

From a defendant’s perspective, a shadow expert can support their legal team in challenging technical points made in the particulars of claim, or in responding to pre-action correspondence, which could even help to nip the dispute in the bud before it gets going. 

Settlement and mediation support 

When settlement opportunities arise, shadow or advisory experts can run different damages quantum scenarios to assist the legal team and client in making and assessing potential offers.  

They can also prepare mediation papers to succinctly articulate key issues and attend mediations to provide technical support. If a formal expert witness has been appointed by this stage, the shadow expert’s involvement can help keep them at a safe distance from such negotiations – to preserve their independence and limit distractions from their core function. 

Appointment of an independent expert witness  

In certain circumstances, an expert providing early-stage input may go on to be appointed as the CPR 35 expert witness, but only if they’re satisfied that their independence is unaffected by their prior work. If progression into the CPR 35 expert role is considered possible or likely, the expert should conduct themselves and their work with this in mind from the outset.  

Where a new expert is to be appointed into the CPR 35 expert role, a shadow expert can help determine the scope of expert evidence required, identify potential candidates, and quickly bring the expert witness up to speed. Care is needed here so that the CPR 35 expert witness isn’t unduly influenced by pre-existing hypotheses. They must also be given access to all relevant documents so they can reach their independent opinion.  

Once the expert witness has prepared their draft report, the shadow expert may be asked by the legal team to identify gaps, potential weaknesses, flawed assumptions or alternative methodologies for consideration. They can also critique the other side’s expert report (in the background). 

Single joint expert cases and expert determinations  

Where a single joint expert (SJE) is appointed – for example, in divorce cases – the parties sometimes each appoint their own shadow experts to provide background support. The shadow expert can prepare their own assessments or valuations, review the SJE’s report, and advise the client and legal team on the strengths and weaknesses of the SJE’s opinions. They can also help devise questions to be put to the SJE, which could alert them to issues to potentially address or amend for in their subsequent expert reports.  

In expert determinations, parties may appoint forensic accountants to help prepare their submissions to the expert determiner – a role akin to a shadow expert. In such cases, most commonly post-acquisition disputes, timely engagement of a shadow expert can be critical. They can advise on actions that need to be taken urgently to maximise chances of success, like preserving and collating evidence of post-deal actions, e.g., communications with debtors – to demonstrate that reasonable collection efforts were made. 

Assisting with trial and hearing preparation  

Leading up to a trial or hearing, the shadow or advisory expert can contribute by helping to brainstorm potential cross examination challenge areas for the party’s independent expert witness to consider in their preparation. Witness coaching must be avoided, however. The shadow expert can also help brief counsel and suggest topics for cross-examination of the other party’s witnesses and experts 

Three practical tips for maximising the value of shadow experts 

To ensure shadow experts deliver the greatest strategic benefit, it’s important to consider how and when they are engaged.  

1. Engage them early 

While shadow experts can be appointed at any stage, involving them early permits their input into case strategy during the formative period. It’s important that quantum of damages assessment is not left too late, by which point costs may have spiralled out of proportion to the potential damages achievable. Identification of key issues – and candid advice on them – is particularly impactful if performed at an early stage. 

2. Define roles clearly 

If different shadow and independent experts are to be appointed, ensure the roles and responsibilities are clearly defined. The shadow expert must avoid preparing their work in CPR 35 expert witness format, as there’s a risk this could perceived as ‘opinion shopping’ if a different expert is formally appointed later.   

3. Benefits of a range of skills 

Unlike a CPR 35 expert witness, shadow experts needn’t be any one single individual. A multidisciplinary firm (such as ours) can be appointed into such a role, providing access to advice across a range of complementary specialisms, including forensic accounting, economics, valuation, tax, insolvency, corporate finance, restructuring and audit, as well as sector expertise. Here, they can be most effective as a strategic partner to the litigation team. 

Some may wonder if the engagement of a shadow expert represents a ‘doubling up’ of expert costs. Their costs are controllable, however, as their tasks can be tightly focused and they can be instructed to start or stop specific analyses as required. This contrasts with a formal expert witness who must consider all the relevant evidence to address their formal instructions. The shadow expert may also save costs in the long run by helping to sensibly shape the case strategy to proceed proportionately based on the issues that matter most. 

Shadow experts: The bottom line  

Forensic accountants and economists acting as shadow or advisory experts can be an invaluable and flexible strategic partner in complex commercial litigation. They can: 

• provide early, candid advice
• give timely input into case strategy
• provide healthy critique to CPR 35 expert reports
• assist with disclosure and settlement negotiations
• support counsel with trial preparation.  

Appointing a shadow or advisory expert can help strengthen a case at all stages and materially improve outcomes for clients.  

A version of this article first appeared in Thought Leaders 4 Disputes Magazine – Year in Review; published in November 2025. 

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