Apparently this is now a reality in serious cases such as rape.
The victim is allowed to give evidence as soon as possible after the incident.

[Link]

I am all in favour of ensuring that rape victims suffer as least as possible but unfortunately the article doesn't explain in detail how this works.

Can you give your evidence before a suspect is charged?

Who will cross examine you? What happens if a suspect starts off with a legal aid lawyer (not very good) but at trial they have a QC who would have asked different questions.

Maybe this is a non issue but having been on a jury recently I saw that after the victim had given evidence their own friends flatly contradicted them on key points much to the surprise of the court.

My gut reaction is that at trial all sorts of surprises occur, the same victim denied her own sworn statement she voluntarily gave to the police which up to that point before defence and prosecution had assume was not in doubt. She then accuused the police of making things up.

One more point