I haven't yet read the book by Dick King-Smith, but I have now seen the movie: The Water Horse: Legend of the Deep, directed by Jay Russell. Featuring the talents of Brian Cox, Ben Chaplin, Emily Watson, Alex Etel (who played "Damian" in Millions), and the beautiful country of New Zealand standing in for Scotland, it tells the story of a confused little boy in wartime, missing his Dad, afraid of water, and suddenly caught up in a magical adventure.
The adventure begins when young Angus MacMorrow finds a strange egg on the shore of Loch Ness. He names the creature that hatches out of it Crusoe, and nurses it in the bathtub of the manor house where his mother is head housekeeper - until one too many close calls with a British artillery unit, which happens to be billeted on the estate, enables the embittered war hero/handiman to persuade Angus to let Crusoe loose in the loch. This only leads to more danger when the gunners mistake the magical monster for a German sub, and Angus has to face his worst fear to save his giant friend. (He is obviously confused, if water scares him more than artillery.)
I was pleasantly surprised by this movie. It is a good, sound, family movie. There are exciting bits, touching bits, funny bits, and yards of footage that are just pure eye candy. The special effects are convincing, Crusoe is adorable, and the lead child actor will win you over (and perhaps give Freddie Highmore a run for his money). I suppose if a few loose ends are left at the end, it will motivate people who (like me) enjoyed the movie to pick up the book as well.