Remember the scene in the Great Escape when Virgil Hilts, "The Cooler King" (Steve McQueen), and Archibald Ives, "The Mole," (Angus Lennie) dreamt up an escape plan to simply dig and burrow in one hit? It didn't work and they again found themselves back in the cooler.
Now, meet Teddy. A friends dog, he likes to dig and burrow too, under their fence to make a bid for freedom and has enjoyed rather more success in his "Blitz Out's," than did Hilts and Ives. My friends solution? Teddy now goes out to play with a bloody great bucket tied to his collar. It hasn't stopped him digging but he no longer gets further than nine inches under the fence.
Perhaps this is where the Germans went wrong with escape obsessed POW's during the war.