I suppose if your in real trouble that's good advice.I have a friend who is a copper and he has always advised me if I were ever to be arrested to go No Comment from the off, no matter what the circumstances unless my solicitor advised me not to. He also strongly advised never ever ever ever speaking to police without a brief present.
But, and this is based solely on my experience, if you treat a copper as 'normal' from the off then you'd be surprised how helpfull they can be.
I got nicked by a lovely wpc some years ago and when she asked if i had anything 'on me' before the search i told her straight. On the way to the cop shop i said she would find outstanding warrants on me. I'll be honest and say i thought i was going down, what with those and the offence id just been nicked for. She told me not to mention the warrants to anybody else in the cop shop.
When the desk sargeant asked what the charge was she said one thing, he wanted a more serious one and they quietly discussed it for a minute. I got the lesser charge.