The plea of res ipsa loquitur: literally means it speaks for itself.
This is a rule of evidence applicable in cases of negligence where want of care is presumed.
It may be relied upon the plaintiff where the occurrence cannot be explained otherwise than the defendants negligence.
For the principle to be applicable the following conditions are necessary:
- Absence of explanation i.e. the plaintiff has no evidence of the negligent actoromission of the defendant.
- Such a thing does not ordinarily happen if care is taken i.e. the occurrence must be consistent with the defendants negligence.
- Whatever occasioned loss or injury was within the exclusive control of the defendant, his servants or agents.
The principle of res ipsa provides prima facie evidence of negligence on the part of the defendant.
Once pleaded the plaintiff, it shifts the burden of proof to the defendant who must now explain the circumstance and if the explanation is reasonable, the plaintiff looses the case for want of prosecution.
This principle was applied in Scott V. London and St. Catherines Dock Ltd.