The deadly reptile was up to 8 feet long and was discovered wriggling and snapping in a bath when officers swooped on the house after uncovering a cannabis factory at a nearby property, a major newspaper reported.
It is believed that the alligator had been bought from a dealer and taken to the three-bedroomed house in Runcorn town, Cheshire county.
Officers also found a King Cobra, three monocled cobras and a rattlesnake while searching the reptile dealer's shop in the neighbouring Warrington town.
Wildlife officers and specialist reptile handling staff had to be brought in to deal with the live animals.
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