Police has banned loud honking at functions.

More cowbell sure, but no airhorn!

The NYPD is banning the loud, celebratory airhorns that family and friends of police officers have blared at promotional events, The Post has learned.

“While celebrating the accomplishments of your colleagues is encouraged, certain behaviors, such as the use of air horns, posters, or other noise-making devices, can disrupt the proceedings, delay the process and harm others. Achievements may be diminished.” the NYPD said in a message to officers. “For this reason, noise generating devices and large posters will not be allowed in the auditorium,,

Sources said the shrill noise suppresses the names of other officers who have received rank increases and generally disrupts the programme, leading to sanctions.

“I think it’s very stupid and unprofessional,” one police officer who has been on the job for more than 20 years said of the boisterous behavior.

“This is supposed to be the NYPD, not a circus,” the source said. “You’ve got your family in there and there’s some bozo blowing the horn like we’re having carnival.”

Promotion ceremonies are usually held at the police academy in Queens, but on Monday they are being moved to NYPD headquarters at One Police Plaza in downtown Manhattan — giving cops more control over what can be brought inside. And what not.

There, security will have the ability to check bags for horns. The NYPD said confetti and face cut-outs – larger-than-life images of police being promoted – would also be outlawed. The policemen who come to the academy generally do not check bags.

Horns have become an issue in the last few years.

Another police officer said, at a promotion function on November 27, horns were blown so loudly that nothing else could be heard.

“When family members walked across the stage to shake the commissioner’s hand, they couldn’t hear their loved one’s name,” Gumshoe said. “It was disturbing.”

The event was the first promotional event attended by Police Commissioner Jessica Tisch in her new role as top cop, and an insider said Horn had clearly unnerved her.

“You should have seen the look on his face,” said the officer, who asked to remain anonymous because he was not authorized to speak to the media.

In video of the incident, Patrol Chief John Chell is seen glaring at the honkers several times.

At One Police Plaza, all attendees will be required to go through security, including a bag check that will easily detect and keep out large horns and other items.

A third source said, “Those things are strong.” “In the headquarters auditorium, you will be deaf. They sound like a train horn in a tunnel. they are annoying.”

Any NYPD member who tries to sneak an airhorn or other contraband into headquarters could be punished, the source said.

The source said of that punishment, “If you think you won’t get caught, you’ll waste time and get a command discipline.” “Jessica Tisch means business.”