Whatever we think about other people's dogs and children, no-one likes poo - not on the beach, not on the pavement, not on sports fields. And no-one on this thread is suggesting that dogs (or anyone else) has a right to poo on the beach -right?
It seems to me, judging by the strength of feeling on this thread, and by my own reaction when my toddler was chased by two big dogs that nothing makes us angrier than an out-of-control dog - except perhaps someone taking your parking space. And yet we don't do anything about it.
But what can we do? You can't go up to other people and ask them to pick up their dog's poo. Nor can you suggest that they control their kids and dogs. Or can you? I would be too scared to do more than tut loudly, I'm afraid. The council can't afford enough wardens; you can't fence off beaches (can you? Would you want to?); you don't really want any more bossy signs telling people what to do and what not to do. More bins would help, I suppose.
What was suggested at our local football club was that we take photos of irresponsible dog owners and shop them to the council. However I would never do that, and if you did manage to get close enough, it's not very likely that they would be fined, or that it would stop them doing it again, and you'd have to prove it anyway. If the council did suddenly get a flood of photos of dogs crapping on the beach, they might do something for a month or so in the summer, but by autumn, the dog owners would be back again.
So this is a situation that calls for poetry. Nothing else will work. Let's have a campaign of poems. Frame them and put them up on the buildings/promenades near the beaches. Invite people to contribute and choose the nation's best dog poo poem.
Here's a line to get you started (think limerick):
Don't let your pooch poo on the beach ...
Prizes for the best continuation.