MrJitty may be able to clarify if I'm right on this, and rather more succinctly...
"Can the jury consider a scenario favourable to the defendant that the defence hasn't put before them tho?"
I'm sorry to say and I am not sure I agree with it but I think it's almost inevitable they can.
I had a stab at answering this upthread - but the short version is the jury, having identified all the facts that have been proven, needs to ask if it can be inferred that PR took some direct action to put Libby in the river
So they must not speculate away individual facts but if they can't be sure he did that because there are other reasonable possibilities, then it is not murder, even where the accused did not plead it. This is what the defence counsel/judge were getting at when they said that his lying does not inevitably mean he did the murder of itself.
It'd be totally different in a civil case. The judgment there would be on the pleadings, the documents by which the parties set out clearly the details they rely upon. They wouldn't get far trying to plead alternative versions of what it was they'd done. Moreso the judge will only base his decision on the arguments. Generally if they haven't argued it he won't consider it even if he's thought of it and he would make a different decision if they had.
"Wouldn't that leave the system open to all sorts of abuse because you could then imagine any scenario within the park that PR hadn't thought of and neither has his defence?"
I'm not sure that follows.
What is open to abuse is the defence knowing what the prosecution case is ahead of trial and them not knowing his, and him hearing their witnesses in court before he gives his evidence...thus enabling him to fabricate his to his advantage.
This is why I was posting about adverse inferences from the Judge/Prosecution
Normally right to silence is absolute. Prosecution can't comment on it and the Judge will specifically warn the jury not to infer anything from no comment answers.
I did a bit more research on police interviews and this is apparently why the suspect assisted by counsel, will read in a prepared statement, and then no comment all the questions. It protects his right to silence later at trial, by commenting things that should be reasonably disclosed.
So hypothetical example - if PR's defence was that he was working as a taxi driver that night - that is something that should be read in - as to why he was in the area. So police can investigate - e.g app use etc - otherwise he can just ambush the prosecution with a fabricated version at trial.
"Surely doubt has to be reasonable and bound by what you've been told?"
Reasonable yes, bound by what you've been told I think no. And there I think we have the nub of the problem in this case.
This is a bugbear of mine and probably why I have way too many posts on it.
BARD standard merely reflects the overall burden of proof on the prosecution.
So in the present case, the jury should review all the circumstantial evidence and ask what can be inferred from it. So IMO, you can infer:
1. Libby was the person screaming in the park
2. PR was the man seen walking out of the park
3. PR raped Libby in the park
4. Libby ended up in the water directly because of the actions of PR
5. PR intended libby to go in the water
6. PR displayed guilty knowledge Libby wouldn't be turning up
= Murder
Only at this point do we ask, is there any other reasonable
possibility and this is where I hesitate a bit.
What tends to happen IMO, is that people tend to henpeck individual facts to BARD standard - that is not allowed. So we shouldn't speculate into existence a mysterious stranger who was "the real killer"
My 02c