Police in Bedford, a commuter town 90 kilometers (55 miles) from central London, posted a picture of a luxuriant cannabis plant growing as tall as the fence in what appeared to be someone's back yard.
In a message posted to Twitter Friday the force said the plant had been "seized today."
"Elderly couple bought shrub at car boot sale, tended carefully-biggest cannabis plant we had seen!!" the message exclaimed.
Further details about the couple—or how either it or police got wise to the plant's true nature—weren't immediately available late Monday.
Bedford Police's message: