Manhattan turnstile jumpers can jump for joy — with both prosecutors and cops admitting they plan to look the other way starting today, sources tell The Post.

The Manhattan DA’s office had in September announced that it will be going easy on most people arrested for fare beating — dismissing their charges provided they completed a program or stayed clean for half a year.

But now, the office has told the NYPD that it will not be prosecuting fare beaters at all. Instead, prosecutors will “DTP,” or decline to prosecute, almost every case brought to arraignment.

Given that, transit cops are expected to not even bother stopping turnstile jumpers, one police source said, predicting a “free for all.”

“Why would a person stop for the cop in the first place?” the source said.

“Everyone is scrambling a bit trying to figure out how the department is going to proceed,” the source said.

“This could be a big tipping point for public order,” the source added.

“Cops will be hesitant to stop fare beaters just to give them a ticket when they can’t effectively arrest and prosecute a person who refuses to cooperate. At that point, why the hell would anyone pay to get on the subway?”

Chief Assistant District Attorney Karen Friedman said this policy shift “marks the next step in our ongoing work to reduce inequality and unnecessary incarceration by ending the prosecution of low-level, non-violent offenses and offenders that do not post a risk to public safety or belong in our criminal courts.”

Police sources, however, say this quality-of-life enforcement in the subways sometimes take dangerous individuals off the street. Fare evaders sometimes have outstanding criminal warrants and are carrying weapons.

Fare beating is also where cop assassin Alexander Bonds had some of his first interactions with police, before he fatally shot officer Miosotis Familia in The Bronx last July.