Bull In Field

We had a nice walk this morning along the estuary from St Clement to Malpas and back across the fields. At one gate there was a "bull in field" warning. We couldn't see any sign of animals so carried on, but in the next field was a large herd of cows and sure enough a bull with them. Now cows and even bulls don't bother me - I'd sooner walk through a field of them than any number of horses. Anyway, coming in the opposite direction was a guy who was obviously very annoyed about the bull and said he was going to contact the council as bulls weren't allowed in fields with public footpaths. My understanding is that it's OK as long as they're with cows but not allowed unaccompanied. Does anyone know the legal position? Have to say that neither the cows or the bull showed the slightest interest in us or the dogs! ?