It’s a slowdown showdown.

At precincts across the city, top brass are cracking the whip on summons activity and even barring many cops from taking vacation and sick days, The Post has learned.

Throughout the city, precincts are being ordered to hand up to borough commanders “activity sheets” indicating the number of arrests and summonses per shift, sources told The Post.

“Police officers around the city are now threatened with transfers, no vacation time and sick time unless they write summonses,” one union source said.

“This is the same practice that caused officers to be labeled racist and abusers of power.”

In at least one precinct, the brass backlash — which comes in the wake of Police Commissioner Bill Bratton ordering cops back on the job after The Post reported a 90 percent drop in ticket writing — is downright ­draconian.

“Everyone here is under orders — no time off” during the summons catch-up blitz, said one cop at the 105th Precinct in Queens.

“And the majority of [new] summonses written aren’t protecting the public in any way.

“But now they’re realizing how much revenue the city is losing and they’re enforcing their will upon us,” he said.

Bratton’s back-to-work edict was still ringing in commanding officers’ ears when the crackdown hit cops on the Thursday/Friday overnight shift at the 105th bordering Nassau County, the officer said.

The lieutenant ordered sector cars from throughout the precinct to converge at Springfield Boulevard and Jamaica Avenue for a driver checkpoint, the officer said.

No one was to return to the precinct or even take a meal break until two summonses were logged, the officer said.

“To have all the manpower utilized for the sole purpose of writing summonses is a very dangerous way to utilize manpower,” he said. “This is not what we’re out here for.”

Back at the station house, memos (above) were posted alerting cops that no new days off would be approved beyond already approved vacation days. And there were to be no sick days without a doctor’s note.