Expert evidence in public procurement claims (Siemens v HS2)

In this article we look at the recent Siemens v HS2 judgment and discuss the clarity it provides where a party seeks permission for expert evidence in procurement litigation.

26 August 2022

The recent judgment in Siemens v HS2 sheds light on applications for permission for expert evidence in procurement litigation.

Siemens Mobility is challenging the procurement of rolling stock and a service contract by HS2. It applied for permission to rely on evidence from an independent expert witness in the field of rolling stock dwell time, door configuration, seat configuration and rolling stock platform interface. HS2 fought the application, supported by the winning bidder. The judgment handed down last week refused permission on all aspects.

Providing clarity on when expert evidence will be permitted in procurement claims

In her judgment, Mrs Justice O’Farrell DBE (the Judge in Charge of the Technology and Construction Court) set out the "material principles” (which can be found at the end of this article) to be considered when a party applies for expert evidence in procurement litigation.

So, why is this important?

Expert evidence is opinion (not factual) evidence. Permission is given only if it is “reasonably required” to resolve the proceedings and is seen as particularly exceptional in procurement litigation. However, it has been permitted in cases involving highly technical matters upon which the Court would not have its own knowledge: for example, in the 2019 Rail Franchising Litigation (actuarial science relating to the funding of defined benefit pensions schemes), Bop-Me’s claim against the Secretary of State for Health and Social Care (industry standards relating to facemasks) and Atos’ claim against the Met Office (supercomputers).

A question arises whether expert evidence in procurement litigation is unusual because of the nature of procurement challenges (the Court exercises only a supervisory jurisdiction in which the issue it must decide is not the respective merits of the tenders but whether the procurement process was lawful) or also because the Court was applying a higher test in procurement claims. This judgment suggests the former.

What does this mean for you?

For any party considering an application for permission to rely on expert evidence (or a challenge involving a highly technical field), O’Farrell J’s five material principles (para. 20) provide the structure that needs to be followed. The judgment also continues trends from recent cases, which might help decide whether the application is likely to be successful: 

  • Recent cases affirm that expert evidence is only allowed where there are highly technical issues the Court recognises it would struggle to understand merely from reading the documents and witness statements (parties might also be able to reach agreement on a common explanation for the Court). However, this of itself might not be enough.
  • Experts are not permitted to “enter the arena” by expressing an opinion on whether there was manifest error in evaluation (even where the evaluation process involved subject matter experts from highly technical fields). Experts are being restricted to providing explanatory evidence to help the Court reach its own opinion on manifest error.
  • The Court is taking a confident stance on what it considers it will be able to understand without expert explanation. O’Farrell J accepted that Siemens and HS2 could need to engage expert advisers to explain complex matters in documents but did not consider that the Court needed independent expert witnesses to provide the same explanation in Court.

Ultimately, Siemens’ application failed because, in many cases, it was unable to tie the expert evidence it wanted to adduce to specific issues in its pleaded challenge (i.e. the evidence sought would have been irrelevant). In the remaining cases, Siemens’ application failed because the issues could properly be explored by the Court based on documents, witness statements, cross-examination and argument.

Advisory experts and confidential information

Independent expert witnesses are different from expert advisers. The latter provide technical support to a litigating party but do not provide evidence in Court (unless they are also factual witnesses). Expert advisers are instructed at the will of the parties. In fundamental contrast, independent expert witnesses must at all times provide impartial evidence and they owe their primary duty to the Court, not the party paying them. The Courts have been consistently highly critical of expert witnesses who seek to advocate for their instructing parties. Independent expert witnesses are permitted only at the discretion of the Court.

The final paragraphs of the judgment hint at (but do not deal with) the difficulties that often arise where a party needs to share with an expert adviser documents that contain another party’s confidential information. This can often lead to intensive interlocutory argument, especially where an expert adviser is essential for the legal team to understand technical matters that might give rise to further or better grounds for challenge. In this case, the Court encouraged the parties to agree amendments to the confidentiality ring.

How can we help?

Both permission to adduce expert evidence in procurement actions and the complexities of confidentiality ring orders (CROs) require careful handling and legal advisory teams with in depth experience of them.

Our market-leading procurement disputes lawyers have built a reputation for litigating high profile cases. As procurement claims and disputes specialists, we regularly act in challenges and disputes for both bidders and purchasing authorities.

If you have any questions on the content of this article or require advice in relation to expert evidence in procurement actions, please contact Chris Jackson.

This article was written by Andrew Walls.

The Material Principles

i) Applicant to identify the issues on which technical explanation may be needed, nature/scope of the proposed expert evidence, and explain why it is needed to resolve the dispute.
ii) It is unlikely that expert evidence will be necessary where the issue for the court is compliance with procurement regulations.
iii) Expert evidence may be permitted where necessary to explain technical issues not capable of agreement and not clear from the factual witnesses/documentary evidence.
iv) Expert evidence may be permitted where necessary for the Court to reach a conclusion on manifest error where the technical issues are particularly complex.
v) Expert evidence is not appropriate where it would have the effect of the expert giving opinions on the matters contested between the parties.

Key contact

Chris Jackson

Chris Jackson Partner

  • Infrastructure
  • Procurement and State Aid
  • Transport

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