Magwitch's shackles

The salt marshes and shingle banks on the Ythan Estuary always remind me of Dicken's Great Expectations. Today, finding these old rusted chains my mind wanders to the day that Pip first met the convict Abel Magwitch after he had escaped from the prison hulk across the mud-flats. Magwitch demanded that Pip bring him food and a file to remove his shackles. 

“Ha!” he muttered then, considering. “Who d’ye live with,—supposin’ you’re kindly let to live, which I han’t made up my mind about?”
“My sister, sir,—Mrs. Joe Gargery,—wife of Joe Gargery, the blacksmith, sir.”
“Blacksmith, eh?” said he. And looked down at his leg.
After darkly looking at his leg and me several times, he came closer to my tombstone, took me by both arms, and tilted me back as far as he could hold me; so that his eyes looked most powerfully down into mine, and mine looked most helplessly up into his.
“Now lookee here,” he said, “the question being whether you’re to be let to live. You know what a file is?”
“Yes, sir.”
“And you know what wittles is?”
“Yes, sir.”
After each question he tilted me over a little more, so as to give me a greater sense of helplessness and danger.
“You get me a file.” He tilted me again. “And you get me wittles.” He tilted me again. “You bring ’em both to me.” He tilted me again. “Or I’ll have your heart and liver out.” He tilted me again.