There is no definitive answer to this question as it is impossible to know for sure the longest turd in history. However, there are some reports of extremely long feces that have been found or recorded throughout history.
One such report comes from an article in The Sun newspaper from 2016, which claims that the world's longest turd was found in a sewer in London and measured an impressive 6ft 2in (1.88m). This would certainly make it one of the longest turds on record, if not the outright winner.
Another contender for the title of longest turd comes from Australia, where a man known only as "Nick" reportedly produced a 7ft (2.1m) long poop after eating 25 hamburgers in one sitting. This incredible feat was unfortunately not officially verified so it remains unconfirmed.
Finally, there is also an unverified story about a man who supposedly produced a 12ft (3.7m) long turd after eating nothing but beans and rice for days on end. If true, this would easily make him the record holder for producing the longest poop ever!