https://www.bbc.co.uk/news/articles/crgyz0erxz1o
'Under Scots law, prosecutors can group two or more offences, each with a single witness, together in order to show jurors that the accused displays a pattern of behaviour.
It is most commonly used in sexual offence hearings, based on a case from 1930.'
...
'Under the doctrine, which applies in rape cases involving more than one alleged victim, juries must return verdicts finding an accused guilty of a similar offence against at least one other complainer.
Lord Hughes told jurors that because they were prepared to convict Mr Duchain on one charge, but not the other three, he would have to change that verdict to not proven.'
In the case referred to, the man was accused of raping three teenage girls in separate offences. The jury found enough evidence to return a guilty verdict in one case, but because they didn't find the same in the other two, the accused walked free.
This is outrageous. The law has to change.