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In a court hearing or trial, the facts must be proved to a certain standard. This standard is, in general, higher in criminal than civil actions.

The standard of proof in a criminal trials is usually beyond reasonable doubt, and in a jury trial the judge has to explain to the jury what that means. It is difficult to give a precise definition, and English law has never tried to impose any sort of statistical measure on 'reasonable doubt'.

In a civil action, the standard of proof is 'on the balance of probabilities'. The side with the burden of proof must prove that its explanation or view of events is more likely than not.