There is a distinct difference between making innuendo without any supporting facts which may be libellous and pointing out referenced discrepancies in witnesses stories.
The first is not allowed, the second is.
Clear enough silly.
The law of defamation recognises two types of meaning:Natural and ordinary meaning of the words
This is not limited to the literal and obvious meaning but includes any inference which the ordinary, reasonable reader would draw from the words.
Innuendo meaning
There are two types of innuendo meaning:
1. False innuendoAlternative meaning which the ordinary reasonable person can read between the lines or infer from the words.
2. True innuendoThis is were the words appear to be innocent to some people but appear to be defamatory to others because they have special knowledge or extra information, an example of this would be, somebody who is said to be getting married which would not be defamatory to the majority of readers, but it would be to the readers who knew that the person was already married and as such would be committing bigamy.
http://www.carruthers-law.co.uk/what-we-do/defamation/defamation-definitions/#.VqZ-1yqLS00