he who asserts must prove / the burden of proof lies upon
According to the age-old maxim, « he who asserts must prove ». The Latin escapes me for the moment. The burden of proof is upon the plaintiff.
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The burden of proof is the obligation on a party to establish the facts in issue in a case to the required degree of certainty (the standard of proof) in order to prove their case.
LEGAL BURDEN OF PROOF - CRIMINAL CASES
The general principle, laid down in Woolmington v DPP is that the burden is on the prosecution to prove the facts essential to their case.
(The Golden Thread of English Criminal Law).
The exceptions to this general principle are where a statute expressly places the legal burden on the accused (e.g.“it shall be for the defendant to prove ....”) or where on interpreting the statute, it implies that the burden is on the accused.
This will usually be the case only in minor offences, where the defendant relies on some form of exemption, or permission to do something, such as licensing matters.
Where it is difficult for the defendant to provide evidence in his defence, or where the offence alleged is a serious one, the courts will generally take the view that the burden is too onerous, and it will rest with the prosecution.
If a defendant does have the legal burden he will only have to discharge it on the balance of probabilities (the civil standard of proof - see below).
LEGAL BURDEN OF PROOF - CIVIL CASES
The general rule is that “he who asserts must prove”, i.e., the burden rests with the plaintiff (the party bringing the action).
The exceptions to this rule include an allegation of frustration where a plaintiff sues for breach of contract. In this situation a defendant would have the legal burden of proving that he was unable to complete the contract due to the fault of another person, or another act, e.g., fire etc.
This is the burden on a party to adduce enough evidence of an allegation to enable the magistrate or judge to allow the issue to be heard and examined in court (i.e., some evidence supporting the contention other than simply the legal representative coming up with a story off the top of his head).
This rule mainly refers to the burden on a defendant to put forward evidence of provocation, self defence or alibi etc.
When enough evidence has been raised, the prosecution would then have to disprove that evidence to the required standard of proof.