For england, wales and NI; No, but there are plenty of public walkways that cross private land, they're almost always marked with signs, although farmers have b

For england, wales and NI; No, but there are plenty of public walkways that cross private land, they're almost always marked with signs, although farmers have been known to make such signposts magically disappear. The end result is that you can essentially 'point in a rough direction' and walk however far you want, however not just on any part of the land. A good OS map, analog or digital, helps.