if an off duty Police Officer (I appreciate they are never off duty as such, much like me) can take such actions without supporting evidence / witness etc they could say almost anything
Very true, but ultimately, if said officer was a bad apple, they wouldn't give a monkeys about fabricating / stretching the truth about something which they saw ON duty... so being off duty probably wouldn't have much distinction, in that instance..
I guess, in the same principle, any member of public could walk into a Police station and provide a statement / make a potentially false allegation against someone for a criminal offence. They'd then be interviewed / possibly arrested etc, but not actually considered Guilty until they plead, or are tried and found to be guility..
So I guess it's the same, if an off duty PC sees something he believe's to be amiss, and provides a statement. Just becuase the PC believe's it's wrong / an offence, doesn't mean it definitely is, as That's a decision that's in the hands of the beak...
It's also worth considering that, just because the guy is a copper, he still has the right to make a statement to Police if he believe's he is the victim of an offence. By retrospectively making a statement, and getting someone else to do the interview, rather than pulling out a warrant card and nicking Dave on the spot, you could argue he has done the correct thing, in order to avoid a conflict of interest..
This is all academic, though. The only thing that matters here, is that the correct evidence is presented to the court from both sides, and that the right decision is reached..
