Basically the judge and/or jury can make an inference from you not offering up a defence during police interview.Johnny Byrne's Boots wrote: ↑Mon Jan 10, 2022 4:34 pm The standard police caution. "It may harm your defence if you do not mention when questioned something you later rely on in court", or words to that effect.
How exactly could it harm your defence?
If you get to court and say “I wasn’t there. I was at my girlfriend’s at the time” and when they asked you where you were during the interview you said “no comment”, the judge and jury can consider why you didn’t just say where you were in the first place. It casts doubt on your testimony at court and in the absence of corroboration from an independent person the judge and jury may believe you’re just making it up and lend little credibility to it. If you give a defence in interview and maintain it in court it is generally seen to be more credible.