The particular case I'm thinking about concerned a charge of benefit fraud. The individual would be guilty if we believed beyond reasonable doubt that :-
- (a) they were in receipt of benefit in the period
- (b) they were gainfully employed during the period
- (c) they hadn't told the benefits agency about their change in circumstances
Proving a negative is difficult, and usually impossible. It's akin to proving that unicorns don't exist (hint: they might be good at hiding). There was no evidence for the existence of this letter, but as William Cowper said : "absence of proof is not proof of absence".
However, when we looked at their story in detail, there were some blatant discrepancies and absences. The decision then was to consider their testimony to be unreliable to a degree that we plain didn't believe it and so to find them guilty as charged.
Unreliable witnesses sometimes tell the truth. So-called reliable ones are sometimes mistaken. Mail can be lost. I admit there was a chance that this letter fell through a wormhole and was eaten by aliens as antipasti.
But I think that beyond my reasonable doubt that this person indulged in some wishful thinking and carried on claiming after they started a low-paying, insecure job. And anyone who defrauds the taxpayer ought to be punished - in this case with some unpaid work.
Just don't get me started on MPs' expenses.