Judges and lawyers are flying blind when it comes to hindsight in costs law
Francis Kendall writes about the role of hindsight in costs assessments
Francis Kendall writes in Edward Fennell’s Legal Diary about the role of hindsight in modern costs assessments, following the recent decision preventing Surrey Police from recovering the full cost of a privately chartered jet used in the extradition of notorious TikTok influencer HSTikkyTokky.
Francis’ article was published in Edward Fennell’s Legal Diary, 20 February 2026, and can be found here.
Last month, Surrey Police were prevented from recovering the full cost of a privately chartered jet that was used to extradite notorious TikTok influencer HSTikkyTokky on the basis that the use of the jet was not “necessary or proportionate”. While the case – and not to mention HSTikkyTokky himself – raised eyebrows, the decision exposed a deeper uncertainty about the concept of hindsight in costs assessments.
In theory, the courts are meant to resist judging spend with the benefit of knowing how the case turned out. This is stated plainly in Francis v Francis and Dickerson: a “proper” item is one that a “sensible solicitor” would have deemed reasonable “in the light of his then knowledge”, not what later became clear. That principle recognises that litigation and operational decisions involve uncertainty and time pressure.
The difficulty is that modern costs disputes are not driven only by “reasonableness” item by item. They are also driven by proportionality, and proportionality can invite a more outcome-shaped evaluation. That tension is easy to see in Kazakhstan Kagazy Plc & Ors v Zhunus & Ors, where the court emphasised that recoverable costs should reflect no more than the lowest amount that could reasonably have been expected to be spent in order to present the case proficiently.
Read strictly, that approach can feel close to second-guessing strategic choices after the event, especially when parties argue that steps were not “needed”.
For practitioners, the result is an unstable decision-making environment. Every stage of a matter involves spending choices with real consequences: how much to front-load, which experts to retain, whether to instruct specialist counsel, and whether to incur urgent costs to reduce risk. Those decisions are taken against incomplete facts and evolving instructions. If a costs judge’s later assessment slides from contemporaneous reasonableness into retrospective optimisation, almost any spend can be portrayed as excessive.
The HSTikkyTokky case illustrates this point. The police argued that chartering the jet was justified by risk considerations and the need to secure safe transport. The judge, however, was not satisfied that a private flight was necessary or proportionate on the material presented. Whether or not one agrees with the outcome, the lesson for costs is stark, and can feel very unfair. Litigants can be criticised and punished for not choosing the cheaper alternative, even where their rationale for what they spent was reasonable and defensible at the time.
Clearer judicial guidance is clearly needed. Courts and practitioners need a consistent framework that explains how proportionality interacts with the rule against hindsight, and what evidence will show that a decision was reasonable when made. Without that, predictability in costs assessment will remain elusive, and confidence in spending decisions will continue to erode.
