Postscript 27 November 2017 for the opposite view in the common law (ius non novit curia) see recently  UKEAT 0130_17_1110 Strickland v Kier.
As readers will be aware, the Rome II Regulation on the law applicable to non-contractual obligations, harmonises Member States’ governing law rules on non-contractual obligations (not entirely accurately known in short as ‘tort’). Article 15 clarifies that the scope of the law applicable is very wide, and indeed includes matters which may otherwise be considered to be procedural (hence subject to lex fori): I explained this mechanism in my posting on Wall. Syred V PZU again concerns Article 15(c) Rome II:
Article 15. Scope of the law applicable
The law applicable to non-contractual obligations under this Regulation shall govern in particular:
…(c) the existence, the nature and the assessment of damage or the remedy claimed;…
The case concerns contributory negligence and quantum of this claim by Mr Syred for injury loss and damage suffered in consequence of a road traffic accident in Poland on 10 February 2010. He and his then girlfriend Kate Cieslar were rear seat passengers in a Fiat Punto, driven by her brother Mr Michal Cieslar, which was involved in a collision with a BMW, being driven by Mr Waclaw Bednorz. The collision caused Mr Syred to be ejected from the Fiat and in consequence to suffer serious injuries, in particular to his brain. He has no memory of the accident. Judgment on primary liability against the Defendants was entered by consent in the two actions on 25 September 2012 and 1 July 2014. Ms Cieslar’s claim in respect of her injuries has been settled.
There is no dispute between the experts for the defence and the plaintiff that a rear seat passenger who fails to wear a seat belt is at fault and negligent for the purpose of the passenger’s civil claims for compensation under Polish law. The experts also agree that the next question in Polish law is whether such negligence caused the injuries or made them worse. They also agree that Polish law in respect of damages for non-pecuniary loss (i.e. the equivalent of general damages for pain and suffering) provides no fixed scales or guidelines relevant to the case and that the judge should seek to assess a reasonable sum taking into account the injuries suffered by the claimant and all the circumstances of the case. Common practice of the Polish civil courts, it was said, is to calculate the non-pecuniary element on the basis of a 2002 table contained in the Ordinance of the Minister of Labour and Social Policy. The Supreme Court of Poland had criticised this practice in civil courts, as too slavish to a social insurance scheme.
In Wall, the CA held that the word ‘law’ in Article 15 of Rome II should be construed broadly and includes practice, conventions and guidelines; so that the assessment of damages should be on that basis. That, Soole J notes here, leaves the question of what the English Court should do if the evidence shows that the foreign courts continue to follow a particular practice despite criticism from the Supreme Court of that country. It is noticeable that the High Court does not wish to impose a precedent rule where there is none (Poland following civil law tradition). However it would be equally impertinent to ignore the criticism of that Supreme Court, that the 2002 table must not be slavishly followed. Soole J therefore ends up taking guidance from the 2002 table, without slavishly following it.
What remains to be seen (as also noted by Matthew Chapman, who alerted me to the case) is whether the High Court may now serve as inspiration for the Polish court. Precedent outsourcing, as it were.
European private international law, second ed. 2016, Chapter 4, Heading 4.8