I remember that one. He was a prize prat. An entitled idiot who was out to insult everyone then say "I didn't do nuffink".You forgot pointed articles. Yawn...
It's all down to discretion on the part of both the user and the police. I daresay if our OP was stopped and searched, there would be a reason for it. If he carefully explained what had happened, he'd very likely be thanked and the knives taken without charge or warning.
A few years ago we got a bloke on BB asking about the law. He'd been charged with possession of a Swiss Army Knife. Strangely it was the corkscrew that caused the problem. As the story unfolded, not only did we discover him to be an arrogant idiot, but that he'd unfolded the corkscrew and told the police something along the lines of he didn't like coppers and wasn't going to cooperate.
Someone tracked down the court number to prove it was a real case, I believe (mostly because it was thought he was just a troll).