At Belzuz Abogados S.L.P., as lawyers specialising in Insurance Law and as experts in civil liability, we never cease to study in depth the doctrines that exempt the general principle of the burden of proof for those who invoke the damage that is the object of the claim, and we are quite familiar, due to our experience as experts in medical civil liability, with the theory of disproportionate damage that we have previously discussed.

In this sense, it should be remembered that the theory of disproportionate damage, due to the abnormal damage created, creates a presumption or, rather, an inference of negligence, hence the expression ‘res ipsa loquitur’ (the thing speaks for itself), being a theory that, in the heart of medical civil liability, due to its evidential proximity and which has been abundantly dealt with by Anglo-American doctrine, being related to the rule on the appearance of proof of German doctrine and the French doctrine of virtual fault.

In synthesis, it is required that a harmful event of the kind that normally only occurs due to negligent conduct occurs, that this event is caused by some conduct that falls within the sphere of the defendant’s action, although the exact details are not known, and that it is not caused by conduct or an action that corresponds to the sphere of the victim himself.

Well, bearing in mind the above, this doctrine has been applied mostly in cases of medical liability, evidently, with examples being that of the patient who goes for a simple operation to remove a small lump of fat and dies during the operation in an inexplicable manner, with this component of inexplicability being the determining factor in the assessment of this liability.

However, assessment outside this sphere has been residual, but the Supreme Court has affirmed in its doctrine, citing First Chamber Judgement 731/2025 of 13 May, which cites numerous doctrines and cases in which, outside the sphere of medical liability, this doctrinal figure has been assessed.

Thus, the aforementioned judgement cites Judgement 298/2004 of 2 April in which the company’s fault is inferred basically in the irregularities of the inspection report, without this fault being inferred on its own:

In particular, this judgement 298/2004, of 2 April, refers to a case in which some workers received a whiplash from the final section of a pipe that was being emptied of concrete, and as a result of the blow they were thrown against a railing that gave way, and the workers fell into the void, dying on the spot. The ruling, upholding the appeal in cassation, and based on the doctrine of disproportionate damage, inferred the company’s fault in the accident by assessing the irregularities found in the inspection report, in the witness statements of other employees and in the expert reports on the lack of safety measures and the failure to secure the materials and equipment at the site where the accident occurred. In other words, when neither the damage itself nor the way in which it occurred reveals fault, its seriousness does not allow it to be inferred without more, and a set of circumstances are required from which it is logical to consider it proven.

However, the First Chamber Judgement 731/2025 of 13 May dismissed the appeal, rejecting the application of this theory on the grounds, in addition to the fact that the activity carried out by the injured girl was not dangerous and did not create a high risk, that fault could not be presumed simply because a harmful event had occurred, since the fault of the teacher or the school could not be inferred by means of an inference; in other words, fault could not be presumed on its own because of the way in which it was caused.

The doctrine of disproportionate damage, in view of the peculiarities and circumstances of each case, represents an exception to the general rule that the burden of proving fault and causal link lies with the plaintiff, on the basis that negligence can be inferred from the disproportionate nature of the damage.

The enormity of the damage acts as evidence that gives rise to an inference of negligence in cases where the harmful result is within the defendant’s sphere of action and is a type of damage that usually only occurs as a result of negligent conduct

In this case, on the basis of the damage suffered by Maria Antonieta when playing a scheduled game in the gymnastics activity at school, we cannot presume the fault of the teacher or the school. We cannot deduce on the basis of maxims of experience that there is a connection that would justify an inference in the sense that we can logically and reasonably infer fault in the conduct of the defendants.

Fault does not arise in itself from the manner in which the accident occurred (another child of the same age fell on Marie Antoinette while playing the game), nor is there any other fact or evidence to support and justify the judicial inference of fault. As is clear from the judgment under appeal, the exercise was suitable for children of Maria Antonieta’s age, and does not entail a potential risk out of the ordinary: ‘We are indeed faced with a risk in an activity with a clear formative determination in its intentionality with rules that do not exceed a high level of complexity, without it having been proven that during the performance of the activity there was an exacerbation of the risk or a clear danger of the same’. The lack of supervision by the teacher during the gymnastics class was also ruled out. And the lack of assistance to the minor on the part of the teachers and the centre itself is also rejected.

In conclusion, the conclusion of the Supreme Court, which has been discarding or applying very strictly objectivist solutions for determining liability, is very appropriate. We should not forget that the general rules of the burden of proof should not be circumvented by the extensive application of theories that reverse the burden of proof, the rules of which, being doctrinally and legally established, should be applied restrictively insofar as their assessment is an exception to the general rule in this regard.

From the Insurance Law Department of Belzuz Abogados S.L.P., we are at your disposal to analyse your liability and insurance problem in the most professional, efficient and solvent manner.