Submitting a flight plan negates the need for a PPR slot.
I will second Chevvron on his reply, PPR is one thing, a flight plan is a completely different thing. Try landing in Schiphol (AMS) without PPR despite having a flight plan. I think they will turn you away quite briskly, or let you land and get very very heavily taxed by the FBO.
Where exactly does the law say that?
With regards to helicopters, I have definitely heard that said before. I am pretty sure it is in law, however, for airfields, I have never come across that. I know for a fact that Bembridge only has PPR on certain days (which is when I believe they also do some gliding [or at least did]). I have heard of places requiring PPR due to a limited number of movements that the airfield is allowed each year. As all other places are trying to kick us GA people out though, our even thinning population would make this rather difficult I would have thought!
So .... why can't the "owner" just publish in the AIP that anyone is welcome to turn up without ringing them first.
Exactly my point. I can't understand why or how it would benefit the airfield to force everyone to call them / email them / fill in an online system / fax them / telegram them first. It seems an unnecessary cost to the airfield to have to have someone there the whole time just to answer the phones (even if they are volunteers, surely the cost of keeping the phone line, internet, heating, tea and coffee, maintenance of the tower...). In New Zealand, most of the airfields I flew into were uncontrolled (most with nobody around - just an honesty box in the corner), no need for PPR, and again everything ran pretty smoothly...