Say the ratio out loud before you open Reasoning — recalling it unprompted is exactly what the exam pays for.
Why it matters
Re Annesley is the working model of total (double) renvoi, also called the foreign court theory, and it is the case that shows why the doctrine cannot be understood as an English rule at all. The English judge decided the case by deciding a question of French doctrine: does France accept a reference back? Because France does, the will failed.
It matters most as one half of a pair. Run Collier v. Rivaz and Re Annesley side by side and the examinable proposition falls out on its own: the same machinery produced opposite results, and the reason lies wholly in the foreign system's attitude to renvoi.
Facts
An Englishwoman died domiciled in France by the English test. By French law she had not acquired a French domicile, for want of the registration formalities French law required.
Her dispositions were valid by English law and invalid by French law, because she had not left two-thirds of her property to her children.
Held
The English judge applied French internal law and held the will invalid.
Reasoning
The chain has five links, and an answer should set them out as a chain.
One. English conflicts law referred the question to the law of the domicile, which by the English test was France.
Two. The reference to French law was read in the wide sense, that is, as including French conflicts rules. Without that step there is no renvoi at all.
Three. French conflicts law would have applied the law of the nationality, England. That is a remission.
Four. English law, asked again, would have referred back to France.
Five — and this is the link that decides the case. France accepts partial renvoi. So a French judge, receiving the English reference back, would have accepted it and applied French internal law. The English judge, sitting in imagination as a French judge, did the same.
That imaginary journey is the definition of the doctrine. This course records it in Cheshire and North's terms: the theory "demands that an English judge, who is referred by his own law to the legal system of a foreign country, must apply whatever law a court in that foreign country would apply if it were hearing the case", and the image the course adds is exact — "The English judge is required to make an imaginary journey to the Foreign land (lex causae) and sit in the court of that country."
Note what the fifth link does to the burden of proof. The result in England turned on a question of French doctrine, which had to be established by expert evidence. Had France refused the remission, the English court would have applied English internal law and upheld the will.
Exam use
It opens: Explain total or double renvoi and Distinguish single and double renvoi with case law.
Set it against Collier v. Rivaz: a British subject died domiciled in Belgium leaving a will valid by English law but not by Belgian law; because a Belgian court would have applied English law as the law of nationality, the English court tested validity by English law and upheld the will. Same doctrine, opposite outcome — and the difference is Belgian and French doctrine, not English law. That contrast is the single most examinable thing in the renvoi section.
Use it in the evaluation essay as the concrete illustration of two objections. First, the doctrine requires the court to familiarise itself with the foreign internal law, the foreign choice-of-law rules and the foreign policy towards renvoi, which "normally involves calling detailed expert evidence as to the state of foreign law" — a course parties will normally seek to avoid. Second, and decisively, total renvoi "can, in practice, be applied only by one country because, if the lex causae were also to apply it, then there would be no way out of the revolving door." Re Annesley works only because France plays a different game; if France also applied the foreign court theory, the regress would be infinite.
It does not decide: that the reference to foreign law must always be read in the wide sense. It does not touch renvoi in contract, which is excluded. And it is not authority on domicile: the divergence between the English and French tests of domicile is the premise of the case, not its holding — for the law of domicile go to Udny v. Udny and Kedar Pandey.