Before a case gets anywhere near a jury the police have to place what evidence they have before ... in England and Wales, the the Crown Prosecution Service under the Director of Public Prosecutions ... in Scotland, the Crown Office and Procurator Fiscal Service ... both of which are responsible for the prosecution of crime.
I believe both these bodies consider and must be satisfied as to the quality of evidence placed before them before allowing a proceeding to trial.
Therefore I would say most cases going to trial must be supported by substantial evidence.
But the case has nothing to do with the UK legal system..
The victim is a British citizen. The suspect a German citizen. The crime was committed in Portugal. Its the responsibility of the Portuguese to put together a case and arrange extradition.
How come we're not hearing from PJ? Why a German prosecutor?
Where's the defence lawyer? 'My client denies any involvement' or 'My client does not wish to comment at this stage'.
Defence lawyers might argue any trial has been prejudiced by media reports.
It doesn't ring true.