What it is referring to is a situation where you rely on some evidence that you could have fabricated, the prosecution is entitled to point out that you had the opportunity to fabricate it.
For example, you claim you were at your friend's house at the time of the crime, but you didn't mention this to the police at the time of the arrest so that they can go and interview your friend to corroborate your alibi.
A jury may take from this that your alibi is not very convincing, because you may have arranged this alibi with your friend between arrest and trial.
In neither England nor the US can someone be convicted based on silence alone. Silence isn't evidence. It is simply the lack of evidence.
What it is referring to is a situation where you rely on some evidence that you could have fabricated, the prosecution is entitled to point out that you had the opportunity to fabricate it.
For example, you claim you were at your friend's house at the time of the crime, but you didn't mention this to the police at the time of the arrest so that they can go and interview your friend to corroborate your alibi.
A jury may take from this that your alibi is not very convincing, because you may have arranged this alibi with your friend between arrest and trial.
In neither England nor the US can someone be convicted based on silence alone. Silence isn't evidence. It is simply the lack of evidence.