A frail old man lived alone in Northern Ireland.
His only son was in Long Kesh Prison, and he didn't know anyone who would help him to dig up his garden, in preparation for planting his potatoes.
He wrote his weekly letter to his son in prison, and mentioned his problem.
After a day or two he received an answer from his son, saying:
"For HEAVENS SAKE, don't dig up that garden, that's where I buried all the GUNS!"
At 4 A.M. the next morning, a dozen heavily armed British soldiers burst into the old man's house, held him at gunpoint, and then proceeded to dig up his back garden from end to end.
After several hours, they had found no guns, and clattered back out of the house again.
Next day, the old man wrote to his son telling him what had happened, and asking him what was going on.
His son wrote back and said: "Now plant your potatoes."