“You do not have to say anything. But it may harm your defence if you do not mention when questioned something which you later rely on in Court. Anything you do say may be given in evidence.”
If the police forget to caution the client I will sometimes make a note of it but say nothing. Sometimes I will remind them. Its a judgement call.
Judges have frequently admitted evidence obtained in breach of the Codes. But they have frequently refused to admit the evidence where there has been a breach of the codes as well. Originally under PACE the police were liable to disciplinary proceedings under s67 if they failed to follow the code. That has been watered down and it could be argued that PACE has no teeth. When it is breached the police are not punished. But it still works. To put it bluntly we do not deal with battered clients who have signed confessions after 'falling down the stairs'. Prior to PACE that was all too common.
Convictions have been quashed where the defendant was not told required information, or not given access to a solicitor or when they were not cautioned or not provided with an appropriate adult or where interview formalities or identification procedures were not complied with.
Its unpredictable but a breach of the Codes has real effects in actual cases.