Being "threatened with arrest" is a hollow threat. He should have told 'em to politely "Do your worst" and after that answered "no comment" to each and every question.
We still have a "Right to Silence" in this country. Admittedly, it is somewhat diminished as the police should point out to you when reading the police caution:
"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.”
What really diminishes the right to silence is people not standing up for that right and saying "no comment" at each and every opportunity.
If arrested tell them your name and show proof of address (or have them ring somebody who will verify that you live at that address) so that you can get bail. After that, answer "no comment" all the way. It's strangely liberating!
And if you begin to feel a bit sheepish answering "no comment" for the 250th time imagine how the person on the other end of the question feels.
Jeremy Thorpe, when questioned by police some years ago, gave a brief explanation as to why he would not be answering questions and to each question after that he simply said "Ibid".
If you adopt that approach you'll probably have to explain to the cops what "ibid" means.
I remember once after a few of us broke into Aldermaston to hold a picnic on the runway I had to answer "no comment" for over half an hour. Eventually the guy gave up.
A good thing too - I had nearly reached the end of my tether. I had only about two "no comment"s left in me before I confessed everything.
Apart from colluding in undermining our right to silence this whole thing surely begs the question why was Klarenberg so ill prepared for an arrest. His naivety is most astonishing. Especially for somebody who spends his life poking the so-called powers-that-be in the eye.