From an article "Characters of Hunting Countries: No. VIII: Durham" in The New Sporting Magazine, Vol. IV, No. 24, April, 1833 (London: Baldwin & Craddock), page 410:

A very ancient tradition is attached to the house of Lambton, which, being somewhat in the sporting line, and admirably related by the historian, we perhaps cannot better employ our pen than in transcribing. It is as follows:—

"The heir of Lambton fishing, as was his profane custom, in the Wear on a Sunday, hooked a small worm or eft, which he carelessly threw into a well, and thought no more of the adventure. The worm (at first neglected) grew till it was too large for its first habitation, and issuing forth from the Worm Well, betook itself to the Wear, where it usually lay a part of the day coiled round a crag in the middle of the water; it also frequented a green mound, leaving vermicular traces, of which, grave living witnesses depose that they have seen vestiges. It now became the terror of the country, and amongst other enormities levied a daily contribution of nine cows' milk, which was always placed for it at the green hill, and in default of which it devoured man and beast. Young Lambton had, it seems, meanwhile, totally repented him of his former life and conversation, had bathed himself in a bath of holy water, taken the sign of the cross, and joined the crusaders. On his return home, he was extremely shocked at witnessing the effects of his youthful imprudences, and immediately undertook the adventure. After several fierce combats, in which the crusader was foiled by his enemy's power of self-union, he found it expedient to add policy to courage; and not perhaps possessing much of the former quality, he went to consult a witch or wise woman. By her judicious advice he armed himself in a coat of mail studded with razor blades, and thus prepared placed himself on the crag in the river, and awaited the monster's arrival. At the usual time, the worm came to the rock, and wound himself with great fury round the armed knight, who had the satisfaction to see his enemy cut in pieces by his own efforts, whilst the stream washing away the severed parts, prevented the possibility of re-union. There is still a sequel to the story; the witch had promised Lambton success only on one condition, that he should slay the first living thing which met his sight after victory. To avoid the possibility of human slaughter, Lambton had directed his father that as soon as he heard him sound three blasts on his bugle, in token of the achievement performed, he should release his favourite greyhound, which would immediately fly to the sound of the horn, and was destined to be the sacrifice. On hearing his son's bugle, however, the old chief was so overjoyed that he forgot the injunctions, and ran himself with open arms to meet his son. Instead of committing a parricide, the conqueror again repaired to his adviser, who pronounced, as the alternative of disobeying the original instructions, that no chief of the Lambton's should die on his bed for seven (or as some accounts say) for nine generations; a commutation which to a martial spirit had nothing probably very terrible, and which was willingly complied with."

Mr. Surtees* adds that the date of the story is of course uncertain, but that nine ascending generations from the late General Lambton (in whom popular tradition affirmed the curse to expire), would exactly reach to Sir John Lambton, Knight of Rhodes, the supposed worm slayer.

[*"Mr. Surtees, of Mainsforth, the accomplished historian of the county"]