Jane Murphy, who heads governmental & PA at the Secret Service, is among four officials demoted yesterday in wake of a series of embarrassing and troubling security lapses.

The raft of blunders at the protective force include the knife-wielding White House fence-jumper who then strolled into the executive mansion, an Atlanta elevator where President Obama shared the car with a gun-toting passenger and the 2011 lackluster response to a gun shot fired at the White House.

The Department of Homeland Security released a blistering review in December of the SS that found "starved for leadership" and sapped by low morale among the rank & file.

Acting SS director Joseph Clancy told Murphy and the chiefs of protection, investigations and technology that they must leave their jobs.

If they fail to resign or retire, the foursome would be re-assigned within the SS or the DHS.

"Change is necessary to gain a fresh perspective on how we conduct business," said a statement from Murphy, who took over for Julia Pearson three months ago.

He's certain that any of the demoted officials "will be productive and valued assets" in other positions at the agency or its DHS parent.